By JOSHUA PRAGER

STOCKHOLM — In neat script, blue ink on white letterhead, Fredrik von Dardel began writing to the stepson he had long been told to leave for dead: “Dear beloved Raoul.”

It was March 24, 1956. He always wrote at his living-room table, his wife, Maria, looking on from a corner of the couch by the phone. On a chest, a spray of flowers she kept fresh stood beside a picture of her son, Raoul Wallenberg.

Mr. Wallenberg, the Swedish diplomat who safeguarded 20,000 Jews in Budapest in the waning months of World War II, vanished into the Soviet penal system in 1945. But the couple, then 71 and 65 years old, believed their son was alive and readied a letter for Sweden’s prime minister to take to Moscow.

“We have been sustained by the hope of one day seeing you among us and again being able to kiss you and hold your hands and hear your beloved voice,” his stepfather wrote in an old and elevated Swedish. “There’s a room here waiting for you.”

Mr. Wallenberg did not come home then, or ever. His end remains unclear. The world now knows the missing Swede as a symbol of humanitarianism — an honorary citizen in four countries, commemorated with stamps in eight and monuments in 12, the subject of scores of films and books.

Unknown, however, is the price his family paid as it tried in vain to bring him home. For six decades, his parents and siblings battled Moscow and their native Stockholm, mounting a search for answers that cost them their savings, careers, relationships, health and, concealed until now, two of their lives.

Also unknown, even to the Swedish foreign ministry — whose file on Mr. Wallenberg dwarfs its record of any king, colony or war — is that the family documented its struggle. Mr. Wallenberg’s late mother and stepfather, who died two days apart in 1979, kept a diary. His half-brother, Guy von Dardel, now 89, compiled a 50,000-page archive.

Together with hundreds of interviews, the family’s thousands of journal entries, letters and documents — most read for the first time by The Wall Street Journal — lay bare the toll of an unending quest.

“It’s a bestial thing,” says Nina Lagergren, who at 87 still spreads her half-brother’s name. “If you don’t know if somebody is dead or if they are alive, you have to go on to look for the truth.”

Raoul Gustav Wallenberg was born on Aug. 4, 1912, in Lidingö, Sweden. His father, a member of a family with wide-ranging influence in banking and business, had died of stomach cancer three months before. Twenty-one years old, the widowed Maj Wallenberg wished to die, too. “But then I felt that I wanted to live, for my little poor fatherless child,” she wrote weeks later.

In 1918, she married Fredrik von Dardel, a healthcare official who would later head the Karolinska Institute, Sweden’s top medical university. Raoul’s half-siblings, Guy and Nina, were born over the next three years.

Raoul’s paternal grandfather, Gustav, groomed the multilingual Wallenberg scion for a banking career and dispatched him to business posts in South Africa, then Palestine.

There, in a kosher boarding house in Haifa in 1936, the Swedish Lutheran met a German Jew whose brother had been murdered by a Nazi. He soon read Adolf Hitler’s Mein Kampf twice, his half-sister recalls.

On Jan. 22, 1944, the United States established the War Refugee Board, an agency intended to protect the endangered populations of Europe. The board asked the Swedish foreign ministry, which staffed a mission in Budapest, to suggest a candidate to run an office there. Word reached Mr. Wallenberg.

Hired by the U.S. and granted diplomatic status by Sweden, Mr. Wallenberg, 31, arrived in Budapest on July 9, 1944. The Nazis had already deported more than half of Hungary’s 750,000 Jews, nearly all to Auschwitz in Poland, where most were killed. Slight, balding and colorblind, Mr. Wallenberg used safehouses, counterfeit passports and bravado to safeguard thousands who remained.

On Dec. 12, he wrote his mother that the Soviets were so close he could hear their gunfire. He expected to be home by Easter. “Dearest Mother,” he concluded. “I will say goodbye for today.”

On Jan. 17, Soviet officers in Budapest arrested him on orders from Moscow.

Sweden’s foreign ministry asked the Soviets about the wellbeing of its mission in Budapest. The Soviets wrote them Mr. Wallenberg was in their custody. According to Soviet and Swedish records, Stockholm didn’t respond.

In mid-February, Mr. Wallenberg’s mother arrived unannounced at the Soviet embassy in Stockholm to appeal for her son. Ambassador Alexandra Kollontay told her “that Raoul was in the Soviet Union and that he was treated well,” Ms. von Dardel recounted to a reporter in 1971.

On March 8, the Soviets stated on Hungarian radio that the Gestapo had murdered Mr. Wallenberg in Budapest.

But assured by the ambassador, Ms. von Dardel was hopeful when, on April 18, she stood on a Stockholm quay awaiting the ship Arcturus. Some of its passengers had worked alongside her son in Budapest. She scanned the disembarking Swedes. Raoul wasn’t there.

Sweden didn’t ask for Mr. Wallenberg’s return, even though the Soviet Union had seized the diplomat in violation of international law. Current and former Swedish foreign ministry officials say that amid worsening East-West relations, neutral Sweden feared petitioning the emerging superpower on behalf of a diplomat financed by the U.S.

Swedish leaders also worried about offending Scandinavian principles of egalitarianism. “How could the socialist government be seen to intercede on behalf of a Wallenberg?” says Jan Lundvik, a retired Swedish ambassador who handled the Wallenberg case in recent decades.

On April 25, more than three months after Moscow had told Stockholm that Mr. Wallenberg was in its custody, Sweden responded. “It is possible that [Mr. Wallenberg] has been in some kind of accident,” Swedish ambassador Staffan Söderblom told the Soviet deputy foreign minister, according to a memo in the Russian foreign ministry archives. The ambassador gave him a more brazen message in December: “It would be splendid if the mission were to be given a reply…that Wallenberg is dead.”

On June 15, 1946, the ambassador reiterated this message to Joseph Stalin. The case, Stalin promised, “will be examined and solved.”

The Swedish foreign ministry told Mr. Wallenberg’s family that it knew nothing of his fate.

The family marked Raoul’s 34th birthday with a dinner in August. It paid his annual taxes in October, a City Hall official classifying him as bortavarande, missing. And it began to seek help through meetings, phone calls and letters addressed to everyone from the World Jewish Congress to United Nations chief Dag Hammarskjöld to actress Ingrid Bergman.

In the coming months, rumors placed Mr. Wallenberg in an Estonian prison, a Slovakian castle and an airplane arriving at the Stockholm airport, where his brother raced in vain in October.

In fact, her son was alive and in Moscow’s Lefortovo prison, according to Russian foreign ministry documents. There, in cell 203, a fellow inmate later recalled to Swedish officials, Mr. Wallenberg tapped coded messages on walls and pipes. Returning in March 1947 from his fifth interrogation, he relayed his interrogator’s withering words: “Nobody cares about you.”

On Aug. 18, 1947, Andrei Vyshinsky, the Soviet deputy foreign minister, sent a letter to the Swedish ambassador in Moscow. It read: “Wallenberg is not in the Soviet Union and he is not known to us.”

Others, too, washed their hands of Mr. Wallenberg. Leaders of Sweden’s Jewish community endorsed the country’s foreign ministry. U.S. officials did not pursue their former representative in Hungary after Sweden’s ambassador in Moscow snubbed their offer to help.

The von Dardels readied for a long fight. They helped found Wallenberg Action, a committee to fund and publicize the search. The mother instructed her younger children to presume Mr. Wallenberg alive until the year 2000.

‘A Dark Cloud’

On Oct. 24, 1952, his 34th wedding anniversary, Mr. von Dardel started a diary. After two paragraphs devoted to his wife, he turned to the stepson who had come to call him Papa: “Raoul Wallenberg’s fate has lain like a dark cloud over our existence.”

The next year, after Mr. von Dardel retired, the couple moved to a ground-floor apartment. There they would press their son’s case for the rest of their lives, he at his table and she on the couch some 10 feet away.

Mr. von Dardel railed in letters and his diary against Swedish officials. He wrote of his wife’s heated words for the foreign minister. “In Germany,” she had told Mr. Undén, “there were a few who worked and succeeded in getting home the many. Here in Sweden, it seems many are now working but are not succeeding in getting home one.”

Ms. von Dardel spent hours on the phone, most often on “negative, chilling calls from the foreign office, when they seemed to be quite without heart,” recalls her daughter, Ms. Lagergren. Ms. Lagergren’s daughter, Nane Annan — the wife of diplomat Kofi Annan — recalls her grandmother’s knuckles whitening as she clutched her phone.

The von Dardels had their distractions. He played solitaire and painted watercolors. She sewed dresses and repaired the home. But they had all but stopped socializing: Sweden’s neutrality during World War II remained a discomfort to Swedes, and the loss of Raoul served as a constant reminder of it. “People have a difficulty meeting somebody who lost someone,” Ms. Lagergren says. “They cross the street.”

On March 24, 1956, days before he was set to travel to Moscow, Swedish prime minister Tage Erlander visited the von Dardels. He told them he shared their wish that he return with their son. Mr. von Dardel sat down to write his stepson of the family’s previous 11 years and their yearning for his return.

Mr. Erlander took their letter. He returned empty-handed. The family Easter, Mr. von Dardel wrote in his diary, was ruined.

On Feb. 6, 1957, the Swedish ambassador in Moscow received a memo from Soviet deputy foreign minister Andrei Gromyko. It stated that Soviet officials had recently found, in the archive of Moscow’s Lubyanka prison, a letter dated July 17, 1947, that prison health director Alexander Smoltsov had written to Soviet security minister Viktor Abakumov.

It began: “I report that the prisoner, Walenberg [sic], who is well known to you, died suddenly in his cell this night, probably as the result of a heart attack.” A notation added that the body had been cremated without autopsy.

The Swedish foreign ministry alerted the von Dardels to the memo the afternoon it arrived. “First they say that they have taken him under their protection,” says Ms. Lagergren. “Then they say that he was murdered…then that he didn’t exist in Russia. They kept with this until they said that he died in 1947, that he died of a heart attack. So naturally, we didn’t take it seriously.”

The von Dardels had hoped that Marcus and Jacob Wallenberg, the powerful brothers at the helm of their family bank, would press the Kremlin to send home the cousin they had called “little Rulle.” But the family acknowledges the brothers wrote just two letters on Raoul’s behalf — one to former ambassador Kollontay in 1947, another in 1954 to a Czech business contact with Soviet ties. They also repeatedly declined to meet with the von Dardels’ group, Wallenberg Action, according to a letter the group sent them in 1954.

“Mommy has been suffering for a long time,” Ms. Lagergren wrote her brother Guy in March 1959, “not having any contact or support from Raoul’s family.”

Peter Wallenberg, 82, says his father, Marcus, who co-headed the family bank, had told him that Raoul’s mother had asked the Wallenbergs not to interfere. “You didn’t do things without total government consent,” he added. “And there was not total government consent in regards to Raoul.”

‘Slippery as an Eel’

Mr. von Dardel increasingly scorned that government. He wrote that ambassador Rolf Sohlman was an “ineffective bastard,” prime minister Erlander “slippery as an eel,” foreign minister Undén “horrible.”

As Mr. von Dardel recorded the drip of witness accounts in his diary over the years, his stepson was aging. But looking out from a picture frame on the green-marble chest top in his parents’ Stockholm apartment, he remained 24.

In 1970, Mr. von Dardel wrote “Raoul Wallenberg: Facts Around a Fate,” a sober recounting of the family’s 25-year search. The book didn’t sell. Says Ms. Lagergren: “People got tired.”

And increasingly uncomfortable. “People look at me as if I was mentally ill,” Ms. von Dardel told a reporter in 1970.

Having endured so many reports of her son’s death, she periodically wished for her own. “She said over and over again, ‘I no longer want to live,’ ” recalls her daughter-in-law, Matti von Dardel.

Maj von Dardel had broken her leg years before and walked with forearm crutches, a bag about her neck to carry things. Her husband, blind for decades in one eye, was losing sight in the other. But both wished to see their diary published. In 1976, they typed its handwritten entries and created an index of the 587 names that populated its pages. No publisher was interested.

On Feb. 6, 1978, Mr. Lundvik visited the von Dardel home. “A very painful meeting with these two old people,” the ambassador wrote in his diary. “That he is alive is taken for granted.”

The next month, Nazi-hunter Simon Wiesenthal — who had earlier reported that Mr. Wallenberg was in an Irkutsk psychiatric hospital — told the von Dardels he’d been mistaken.

On April 28, 1978, Mr. von Dardel concluded the diary begun nearly 10,000 days before. On its final page, he wrote two English words: “stone wall.”

On July 10, Mr. von Dardel wrote to Swedish doctor David Hummel. According to a book written by a colleague, Dr. Hummel was helping people to die with insulin and Diminal Duplex, a sleeping pill. “I would like to give you my wife’s and my thanks,” Mr. von Dardel wrote, his script large and slack, “for your regards and for your prescription.”

Soon after, Mr. von Dardel lay in his bed and raised a spoonful of sleeping pills to his lips. “But,” says his daughter-in-law, “he dropped it and couldn’t find his pills.”

In 1979, Swedish papers reported that a former Soviet prisoner testified to the Swedish foreign ministry that Mr. Wallenberg had been in a prison in the city of Vladimir until at least the summer of 1975. But holes now emerged in this testimony, too.

Mr. von Dardel, aged 93, decided again to end his life. On Feb. 12, he died in his bed.

Raoul Wallenberg’s mother, again widowed, lay on her sofa two days later and swallowed an overdose of barbiturates.

Nina Lagergren arrived shortly after. Her mother, still alive, asked Nina to promise that she and Guy would keep fighting for their older brother — and presume him living, as she had long instructed, until 2000.

Nina gave her word.

Mourners laid a blanket of yellow, white and pink flowers over a pair of closed coffins. In their parents’ death notice, the siblings listed three surviving relatives: Nina Lagergren, Guy von Dardel and Raoul Wallenberg.

Siblings’ Secret

Together, Nina and Guy would carry until now the secret of their parents’ suicides. But they would fulfill their mother’s deathbed request in ways that increasingly pulled them apart.

After their half-brother’s disappearance, Guy von Dardel often turned from his wife, two daughters and career as a particle physicist in Geneva to help his parents pursue Mr. Wallenberg. He chipped at diplomatic stonewalls and mined contacts — persuading fellow physicist Albert Einstein, for example, to argue Mr. Wallenberg’s case in a letter to Stalin.

Nina Lagergren, a housewife and mother of four in Stockholm, tried to provide her parents daily respite from their singleminded search. “I thought the best I could do for Raoul was to give them a real life,” she says.

In the days after their parents’ deaths, Mr. von Dardel, 59, asked his sister, 57, to help him form an advocacy group for Mr. Wallenberg. Ms. Lagergren wondered to a friend, Nobel Foundation president Stig Ramel, whether she should take up the mantle without traumatizing her family. She later recalled that he responded: “Can you do anything else?”

Ms. Lagergren soon asked her missing brother’s cousin for help. Marcus Wallenberg offered funding and an office. Within months, the Raoul Wallenberg Association had a board and members.

Throughout the spring and summer, Mr. von Dardel and Ms. Lagergren sowed word of their sibling, meeting with dignitaries from Israeli Prime Minister Menachem Begin to U.S. Senator Joseph Biden. By fall, Raoul Wallenberg committees were flowering in Jerusalem, London, New York and Stockholm.

Ms. Lagergren began to dress in red and blue, she says, “for courage.” She found strength meeting Jews shielded by Mr. Wallenberg, including U.S. politician Tom Lantos and his family. “I felt a very strong emotional sensation looking at these lovely people, all so deeply committed in wanting to pay their debt to their saviour,” she wrote in July 1979.

In December, Mr. von Dardel took the siblings’ search to Moscow. He tried to drum up support for a Soviet-Swedish commission to research his brother and persuaded fellow physicist Andrei Sakharov to travel to sites where former prisonmates of Mr. Wallenberg were rumored to be.

In January 1980, Sweden’s foreign ministry declassified some 2,000 documents — about one-ninth of its holdings at the time. Ms. Lagergren told reporters: “We must look forward and act with certainty that Raoul is alive.”

Mr. von Dardel wrote his sister: “You are doing a fantastic job.”

In February, the first anniversary of their parents’ suicides, Ms. Lagergren placed flowers on their adjoining graves. “I think that mom and dad in heaven probably are quite pleased with developments,” she wrote to her brother. “We haven’t been able to free Raoul, but his name is known as never before.”

Mr. von Dardel let his sister know, however, that he saw little point in publicizing Raoul’s exploits. “Next Sunday,” he wrote to his sister on June 22, 1980, from Palo Alto, Calif., where he was on a teaching sabbatical at Stanford, “Mrs. Fleishacker, who is it seems one of the ten upper class people in San Francisco, opens her house in honour of Raoul. I do not normally find that Raoul is much helped by social events.”

But such events drew Diaspora dollars and press. Mr. Wallenberg’s story joined the writings of Elie Wiesel, Anne Frank and William Styron in the Holocaust education of a postwar generation.

On Oct. 5, 1981, Ronald Reagan declared Mr. Wallenberg an honorary U.S. citizen — its second, after Winston Churchill. “What he accomplished was of biblical proportions,” the president said in the White House’s Rose Garden, the two siblings standing alongside.

Sweden, however, had no Raoul Wallenberg street, stamp or statue. And when a Soviet submarine ran aground on its coast in late October, Stockholm ignored a call from Mr. Lantos — now a U.S. representative — to trade its crew for answers about Mr. Wallenberg. It towed the sub into international waters

“The place where we are met with the most indifference,” Mr. von Dardel wrote in a letter two months later, “is still our and Raoul’s native country.”

In 1984, Mr. von Dardel stepped up his assault, suing Moscow in a federal district court in Washington, D.C. “Von Dardel v. Union of Soviet Socialist Republics” alleged that the arrest of a Swedish diplomat was illegal and demanded the return of Mr. Wallenberg or his remains. The court ruled in Mr. von Dardel’s favor. But the Soviet Union didn’t respond and the case was eventually dismissed. He retired to search full-time for his brother.

Ms. Lagergren, meanwhile, assembled a book of letters her mother wrote about Raoul when he was young. She headlined the New York premiere of a Raoul Wallenberg movie in the fall of 1984. The next spring, at a black-tie dinner in her missing half-brother’s honor, she dined on gravlax and reindeer alongside Henry Kissinger and Max von Sydow and lamented that her mother hadn’t received such support.

Mr. von Dardel didn’t attend either event.

Swedish reticence and Soviet intransigence began to give way. In 1987, Sweden issued a Raoul Wallenberg stamp and dedicated a Stockholm square to him. Soviet leader Mikhail Gorbachev introduced an era of openness.

Mr. von Dardel traveled to Moscow in 1987 and 1988 to meet again with Mr. Sakharov, relaying locations near Tbilisi and Leningrad where his half-brother was rumored to be. Mr. Sakharov and his wife, Elena Bonner, set off. “I was in a state of urgency,” Ms. Bonner recalls.

The next year, the Soviet ambassador in Sweden summoned the siblings to his embassy and said they were invited to Moscow. “Their faces were glowing,” he later recalled to a Swedish newspaper.

On Oct. 16, 1989, a Soviet official set a wooden box before Ms. Lagergren and Mr. von Dardel. The siblings, 68 and 70, beheld what had been seized from their half-brother 45 years before: an address book, calendar, car registration, cigarette case, diplomatic passport and stacks of old money — Bulgarian leva, Hungarian pengos, Swedish krona, Swiss francs and U.S. dollars. The Soviets reiterated that Mr. Wallenberg had died in 1947 and nearly all his case files had been destroyed.

Mr. Sakharov, too, told the siblings that he believed their brother was dead.

Memories of Brother

The two returned home from Moscow, their paths now increasingly determined by their pasts.

Ms. Lagergren recalled her missing brother vividly. He had loved to dance and mimic, imitating German officers and French diplomats at a 1943 Christmas party. He remained everpresent in her home — a bust of Raoul in her entryway, his architectural sketchings in her study, the wooden box from Moscow now tucked in her basement.

She spoke about him weekly at her Stockholm association but not to her aristocratic circle of friends. Ms. Lagergren began to take anti-depressants and sought refuge in her yard, tufts of corydalis ringing the trunks of her apple and pear trees. “I must have this dual life to be able to exist,” she says.

Mr. von Dardel had not been as close to his brother and kept few of his possessions. He struggled to recall him, says his wife, Matti. A doctor suspected Parkinson’s disease. Mr. von Dardel’s face became increasingly still. Soon after, he wept without expression when he listened to Raoul’s college classmates recount how the missing man had hitchhiked, shopped at Montgomery Ward and liked Laurel and Hardy.

The former physicist turned to research. He created the Soviet-International Commission on the Fate and Whereabouts of Raoul Wallenberg, which gave way to a Swedish-Russian governmental group. Its members hoped the Soviet Union’s collapse would loosen archives and officials.

Mr. von Dardel distanced himself from the Raoul Wallenberg Association he had founded with his sister. The dues of its 1,000 members funded an annual concert and helped spread his name. There was now a Raoul Wallenberg daffodil, a Raoul Wallenberg wax statue in a Swedish museum, a Raoul Wallenberg entry in the Guinness Book of World Records (“Greatest Number of People Saved from Extinction”). In 1991, Mr. von Dardel did not attend the association’s board meeting and in later years did not return.

“I have found these activities relatively uninteresting, if not to say tasteless, as long as Raoul’s destiny is unsolved,” he wrote in June 1994 to Peter Wallenberg, who had supported the association since assuming his family’s helm in 1982. Mr. von Dardel asked the banker for $50,000 to fund his search.

Peter Wallenberg declined the request. (He says he was instructed to do so by Ms. Lagergren; she says this is false.) Soon, the Wallenberg bank also refused Mr. von Dardel access to its archive, the family lawyer stating on Swedish television that it was open only to “serious research.”

Mr. von Dardel commissioned an FBI sketch of what his brother would look like at age 80. He wrote his sister to ask for Raoul’s dental records. He traveled to Russia 15 times in 1994 alone — the 75-year-old man enduring scabies, hypothermia and, when he approached a man Soviet files say interrogated his brother a half-century before, a cane swung at his head. He began to question the motives of those he’d hired to help him, letters show, and wondered if his phone was tapped.

Mr. von Dardel had used his savings, a few hundred thousand dollars, to fund his research, his wife says. He’d spent another $100,000 from his youngest daughter. By 1995, 50 years after he began looking for his brother, he’d all but stopped speaking to his sister.

Using his wife as an intermediary, she says, he told Ms. Lagergren he wanted to tap the account Mr. Wallenberg had left behind. Ms. Lagergren acquiesced. Over the next five years, Mr. von Dardel withdrew $130,000, Mr. Wallenberg funding his own search.

The siblings’ Raoul Wallenberg Association closed its doors in 1999. Ms. Lagergren opened the Raoul Wallenberg Committee. She was its sole member.

Apology From Sweden

The year was 2000. The siblings were to assume their brother dead. But Ms. Lagergren couldn’t bring herself to do so. The time, she says, “was not ripe yet.”

In January 2001, the Swedish-Russian group that included Mr. von Dardel published its final report on Mr. Wallenberg. It was inconclusive.

Days later, Swedish Prime Minister Göran Persson phoned the siblings. Recalls Mr. Persson: “It was an expression of apology from the kingdom of Sweden.”

The prime minister failed to comfort. “How can one call after so many years?” asks Ms. Lagergren. “Just call?”

In short order, Mr. von Dardel broke his hip, got a pacemaker, caught pneumonia and, says his family, spoke less and less. He stopped speaking of his brother.

His doctors were unsure why. His family wasn’t. “You understand now,” says his daughter, Louise, “that the illness is Raoul Wallenberg illness.”

In 2003, a commission appointed by the Swedish prime minister published “A Diplomatic Failure,” an open critique of Sweden’s policy toward its missing diplomat. “Diplomatic opportunities that might have helped Wallenberg were missed,” says Sweden’s current deputy foreign minister, Frank Belfrage.

Mr. Lundvik, the ambassador who long handled the Wallenberg case, is more blunt. “The Swedish government did not want him back,” he says.

In 2005, Mr. von Dardel’s younger daughter, Marie Dupuy, emptied the contents of her father’s living-room closet into her Peugeot and drove it to her home in Versailles, France. She divided some 50,000 pages into 75 bins. One was devoted to her father’s career in physics, 74 to his missing half-brother.

Here were the 32 years before Mr. Wallenberg disappeared — a tracing of his newborn foot, an invitation to a 1944 cocktail party he hosted. But mostly, here were the 61 years that came after — pleas for information from soldiers and girlfriends, lawsuits and librettos bearing his name. Here was the account of the Pole who claimed to have given Mr. Wallenberg extra soup rations. Here was the thank-you note, dated 1978, to the doctor who would help Raoul’s parents die.

In September 2007, Ms. Lagergren visited Geneva and stopped to see her brother. He didn’t speak. “The years when he was on the commission must have been very trying for him,” she says.

On Aug. 4, 2008, dressed in red and blue, Ms. Lagergren clipped three red roses from her garden. She placed the flowers, as her mother had, next to the portrait of Raoul that had stood in her parents’ living room. Ninety-six years after the day he was born, she still presumed him living.

Eight days later, Mr. von Dardel sat silently in Room 233 of a Geneva hospital. Belted to a recliner chair, his hospital bracelet sliding over his thin right forearm, he listened to this reporter recount his family’s search.

“I think it was very unfair,” he said in a faint voice, of the brunt of two suicides on his sister. “Nina was in the center position.”

Talk turned to the search.

“One should go to the top,” he said.

Vladimir Putin?

“Yes.”

What would he like to tell the Russian leader?

Days before turning 89, Mr. von Dardel summoned his strength: “If we sit down…try to find out…the real hope would be if new information…”

Did he still think about Raoul?

“Yes, I do,” Mr. von Dardel answered in his strongest voice.

Later, he added: “I see him in Russia.”

* * *

Corrections & Amplifications

Earlier versions of this article misidentified the birthday that the family marked with a dinner. It was Raoul’s 34th birthday.