Daniel Edward Cohen

Daniel Cohen, a children’s book author who exhaustively sought justice for his 20-year-old daughter and the 269 other victims of the terrorist bombing of Pan Am Flight 103 in 1988 over Lockerbie, Scotland, died on Sunday in Cape May, N.J. He was 82.

His wife, Susan Cohen, said the cause was sepsis. He also had a stroke in 2009 that had left him largely unable to speak.

Theodora Cohen, who was known as Theo, was a Syracuse University student flying home from a semester in London when a bomb exploded at 31,000 feet on Dec. 21, 1988. The bombing killed all 259 passengers and crew members and 11 other people on the ground. Theo was their only child.

“I felt like killing myself,” Susan Cohen said in a telephone interview. “It was Daniel who said, ‘No, Susan, we fought for her when she was alive, we’ll fight for her now that she’s died.’ ”

Mr. Cohen and his wife, who is also a freelance writer, became two of the bereaved families’ loudest voices, speaking often to the media and officials of the administrations of Presidents George H. W. Bush and Bill Clinton and writing a book about the investigation into the explosion and their own ordeal.

The couple relentlessly pressed investigators to identify their daughter’s killers; like other families, the Cohens did not believe responsibility stopped at the single Libyan convicted of the bombing.

But they were frustrated by what they called Mr. Bush’s inaction and Mr. Clinton’s refusal to retaliate severely enough against Libya’s dictator, Col. Muammar el-Qaddafi, whom they believed was guilty of state-sponsored terrorism.

In 1998, when victims’ families and President Clinton gathered at the Lockerbie Memorial Cairn at Arlington National Cemetery to commemorate the bombing, Mr. Cohen shook Mr. Clinton’s hand but rebuked him for his “lousy policy” regarding Libya.

“Daniel yelled at him,” Ms. Cohen said. “We were the most aggressive of the families.”

Nearly two years later, the Cohens traveled to Camp Zeist, a former NATO air base in the Netherlands, for the trial of two Libyan intelligence agents indicted in the bombing. Mr. Cohen distributed photographs of his daughter outside the courthouse.

“This is my daughter, Theo — Theodora Cohen,” Mr. Cohen told passers-by. “Now, if the trial and conviction of two low-level thugs is justice for this murder and for 269 others, fine, but I don’t think it’s going to be.” He added, “I’m not here so much because I expect justice, but for her sake and for her memory.”

In early 2001, the Scottish court presiding in the Netherlands convicted only one of the two Libyans on trial, Abdel Basset Ali al-Megrahi, and acquitted the other. When Mr. Cohen learned that Mr. Megrahi had been sentenced to a minimum of 20 years in prison, he said, “Of course it’s not fair, but what’s fair for mass murder?”

Daniel Edward Reba was born in Chicago on March 12, 1936. His father, Edward Reba, and his mother, Suzanne Greenberg, divorced when he was very young. Soon after that, his mother married Milton Cohen, a left-wing social reformer, and Daniel took his stepfather’s surname.

After graduating from high school in 1954, he enrolled in the University of Illinois at Navy Pier in Chicago. He later graduated from the university’s campus in Champaign with a bachelor’s degree in journalism.

After working at Time magazine and Science Digest, Mr. Cohen began writing books — nearly all for children and teenagers — about ghosts, U.F.O.s, the occult, ESP, vampires, werewolves, conspiracies, cloning, weather and the human genome. He wrote biographies of the astronomer Carl Sagan and Jesse Ventura, the pro wrestler who was later elected governor of Minnesota. In all, he wrote nearly 200 books.

With his wife, Mr. Cohen wrote “When Someone You Know Is Gay” (1989), an introduction to homosexuality that Publishers Weekly said “performs a needed service: While gay teens will read it, learn and feel less alone, the target audience is the friends and classmates of gays.”

Their most personal book was “Pan Am 103: The Bombing, the Betrayals, and a Bereaved Family’s Search for Justice” (2000), which recounted their dramatically altered lives without their daughter.

“I was a kinder and gentler person before Dec. 21, 1988,” Mr. Cohen wrote. “Now I’m angry and bitter. Early on, after we found out that this was a bombing, we had a press conference, and I remember myself saying, I don’t want any bombing in retaliation for this act. A couple of years later, we were talking to a group down at the United Nations and I found myself saying: Maybe I was wrong about that because nothing else has happened. We should retaliate. We should bomb them.”

The United States did not attack Libya as Mr. Cohen had hoped. Rather, when the victims’ families sued Libya, the country agreed to pay $2.7 billion to compensate the 270 families — or $10 million each. But the Cohens were outraged at the underlying deal making, which required the United Nations to lift its sanctions against Libya. In an op-ed article for The Wall Street Journal in 2002, the Cohens wrote that the deal “is another attempt to buy our support for the rehabilitation and enrichment of the guys who killed our daughter — or at least to shut us up.” They ultimately accepted $4 million from Libya, minus legal fees, for Theo’s death. They took the first payout after the United Nations’ sanctions were lifted in 2003 but refused the next two after the United States lifted its sanctions and removed Libya from a list of state sponsors of terrorism. They believed those actions had legitimized Qaddafi.

(They had also received $575,000 from Pan Am’s insurers after a 1992 civil trial found the airline liable for damages, concluding that its security had been inadequate to prevent the bombing.)

James Kreindler, an aviation lawyer who took the lead role as a member of the plaintiffs’ committee in the families’ lawsuit against Libya, said, “Dan was really one of the fighters in the core group that was the most active.” He added, in a telephone interview, that Mr. Cohen had been especially effective in helping to persuade Congress to pass a law in 1996 that let the families sue Libya.

When Mr. Megrahi — ill with the prostate cancer that would kill him three years later — was given compassionate release in August 2009, Mr. Cohen’s voice had by then been silenced by the stroke he had that year. But Ms. Cohen answered for both of them, castigating the Scottish government for letting Mr. Megrahi out of a prison in Greenock, Scotland.

“It’s the most craven, cowardly thing I’ve never seen,” she told CNN. “It makes the pain worse. This isn’t about compassionate release but about oil interests and lobbyists pressing governments to get what they want.” The next month, Jack Straw, the British justice minister, confirmed those suspicions when he conceded that business deals — specifically regarding oil — were part of the country’s calculation in negotiating with Libya for Mr. Megrahi’s freedom.

In addition to his wife, the former Susan Handler, Mr. Cohen is survived by a sister, Jean Cohen.

The Cohens and other families relived their pain and desolation in “Since: The Bombing of Pan Am Flight 103,” a documentary by Phil Furey that has been shown at festivals for the last two years and will be shown on television this year.

In an interview that he recorded for the documentary in 2008, Mr. Cohen described the raw emotions he continued to feel at the loss of his daughter.

“If you lose your parents, you become an orphan,” he said. “If your spouse dies, you’re a widow or a widower. What are you if you lose your child? What’s the name for that?”