Mark Lane, Early Kennedy Assassination Conspiracy Theorist, Dies at 89

Mark Lane, the defense lawyer, social activist and author who concluded in a blockbuster book in the mid-1960s that Lee Harvey Oswald could not have acted alone in killing President John F. Kennedy, a thesis supported in part by the House Select Committee on Assassinations in 1979, died on Tuesday at his home in Charlottesville, Va. He was 89.

The cause was a heart attack, his friend and paralegal Sue Herndon said.

The Kennedy assassination, one of the manifest turning points of the 20th century, was the pivotal moment in Mr. Lane’s life and career. He would go on to raise the possibility of conspiracy in the assassination of the Rev. Dr. Martin Luther King Jr. five years later, but it was his Kennedy inquiry that made his name.

Before the president’s murder on Nov. 22, 1963, Mr. Lane was a minor figure in New York’s legal and political circles. He had organized rent strikes, opposed bomb shelter programs, joined the Freedom Riders, took on civil rights cases and was active in the New York City Democratic Party. He was elected a State Assemblyman in 1960 and served one term.

After the Kennedy murder, Mr. Lane devoted much of the next three decades to its investigation. Almost immediately he began the Citizens’ Committee of Inquiry, interviewed witnesses, collected evidence and delivered speeches on the assassination in the United States and in Europe, where he befriended Bertrand Russell, the British philosopher, who became an early supporter of Mr. Lane’s efforts.

With a strong personality and a yen for visibility and risk, Mr. Lane also began cultivating and attracting high-profile clients. In the 1960s he worked with Jim Garrison, the New Orleans district attorney who was investigating the Kennedy assassination in a case that Oliver Stone featured in the 1991 movie “JFK.” He represented leaders of the Wounded Knee uprising by American Indians as well as the cult leader Jim Jones, narrowly surviving the mass suicide of Jones and his followers in Guyana.

Mr. Lane emerged as one of the most important experts on the Kennedy assassination after President Lyndon B. Johnson appointed the Warren Commission to investigate it. Mr. Lane testified before the commission in 1964 and was a legal counsel to Marguerite Oswald, the suspect’s mother.

He published the results of his inquiry in August 1966 in “Rush to Judgment,” his first book, which dominated best-seller lists for two years. With a trial lawyer’s capacity to amass facts and a storyteller’s skill in distilling them into a coherent narrative, he asserted that the Warren Commission’s conclusion that Oswald was the lone gunman was incomplete, reckless at times and implausible.

The book raised doubts about Oswald’s marksmanship and the expertise of police agencies, and it sought to ridicule the Warren Commission’s conclusion that one “magic bullet” could have struck and grievously injured President Kennedy and Gov. John Connally of Texas and have still emerged essentially intact.

Mr. Lane’s findings were disputed aggressively by the government. Still, the financial success of “Rush to Judgment” and its conclusions prompted the development of a cottage industry of books on the assassination, written both by those who believed in a conspiracy and by those who did not. More than 2,000 such titles were eventually published.

Mr. Lane was among the genre’s most active contributors. In 1967, the same year Mr. Lane produced a documentary film version of the book, with the same title, Calvin Trillin of The New Yorker called him one of the foremost Kennedy “assassination buffs.” The next year, Mr. Lane published “A Citizen’s Dissent,’’ his response to the Warren report’s defenders.

His book “Rush to Judgment” was adapted into the 1973 feature film “Executive Action,” starring Burt Lancaster and written by Mr. Lane with help from the formerly blacklisted screenwriter Dalton Trumbo. Mr. Lane produced a second documentary on the Kennedy assassination, “Two Men in Dallas,” and published “Plausible Denial,” another book arguing that the C.I.A. was involved in the Kennedy murder. Both the film and the book came out in 1991.

Mr. Lane relished his heightened national attention. The comedian Dick Gregory chose Mr. Lane to be his running mate in several states in a write-in presidential candidacy in 1968 under the banner of the Freedom and Peace Party. The campaign collected nearly 50,000 votes.

While working with Vietnam Veterans Against the War in 1970, Mr. Lane befriended Jane Fonda and appeared with her on “The Dick Cavett Show” on ABC. He represented the American Indian Movement in 1974, joining the lawyer William M. Kunstler in successfully defending Russell C. Means and Dennis J. Banks against federal charges of conspiracy, assault and larceny in leading the uprising at Wounded Knee, S.D., in 1973, when the town was occupied in a 71-day standoff with federal marshals and F.B.I. agents.

During this period Mr. Lane joined Mr. Gregory and other civil rights leaders in investigating Dr. King’s assassination in 1968. He and Mr. Gregory published their findings as co-authors of the book “Murder in Memphis” (first released in 1977 as “Code Name Zero”), which suggested that the F.B.I. may have been involved in a conspiracy behind the killing.

Mr. Lane also worked with Representative Thomas N. Downey, a New York Democrat, to draft legislation that in 1976 established the House Select Committee on Assassinations to investigate the murders of Kennedy and King. Mr. Downey was its first chairman. Mr. Lane represented King’s assassin, James Earl Ray, during that period and in testimony before the committee unsuccessfully sought his release.

In its final report, in 1979, the committee went further than any branch of government to support the central points of Mr. Lane’s thesis about Kennedy’s murder. It concluded that the F.B.I. and Warren Commission investigations of the assassination were flawed.

The committee also found that while Oswald fired three shots, one of which killed President Kennedy, a “high probability” existed that a second gunman was present and that the president “was probably assassinated as a result of a conspiracy.” The committee, though, was “unable to identify the other gunman or the extent of the conspiracy.”

In its investigation of the King assassination, the committee criticized Mr. Lane, however, for providing evidence that it regarded as unsubstantiated. “In many instances, the committee found that Lane was willing to advocate conspiracy theories publicly without having checked the factual basis for them,” the authors of the final committee report wrote. “In other instances, Lane proclaimed conspiracy based on little more than inference and innuendo. Lane’s conduct resulted in public misperception about the assassination of Dr. King and must be condemned.”

Mr. Lane was undeterred. “It seems clear,” he wrote in 1992, “that the people of this nation have a different agenda from the politics of suppression, disinformation, perjury and subornation of perjury readily embraced by their leaders.”

Mark Lane was born in Brooklyn on Feb. 24, 1927. He was the middle of three children of Harry Lane, an accountant, and Betty Lane, a secretary. He served in the Army after World War II in Vienna and returned to Brooklyn. He earned an undergraduate degree at Long Island University and a law degree at Brooklyn Law School.

His first two marriages ended in divorce. He is survived by his wife, the former Patricia Erdner; three daughters, Anne Marie Lane, Christina Bel and Vita O’Shea; and four grandchildren.

Mr. Lane moved to Charlottesville in the 1970s and practiced law there. In the late ’70s he represented Jim Jones, leader of the California-based People’s Temple cult. Mr. Lane was in Jonestown, Guyana, where Jones and his followers had moved, on Nov. 18, 1978, the day that Representative Leo Ryan was killed and more than 900 other people died of cyanide poisoning. Mr. Lane survived by fleeing into the jungle. He wrote about Jones and the deaths in “The Strongest Poison” (1979).

In the mid-1980s Mr. Lane successfully defended the far-right Liberty Lobby and its publication, The Spotlight, in a defamation case brought by E. Howard Hunt, the C.I.A. agent and Watergate co-conspirator.

Mr. Lane’s passion about the Kennedy assassination never seemed to wane, His final book on the subject, “Last Word: My Indictment of the C.I.A. in the Murder of JFK” was published in 2011.

His autobiography, “Citizen Lane,” was published in 2012, with an introduction by the actor Martin Sheen. A documentary of the same name, written and directed by the actress Pauley Perrette, came out in 2013.

“I’ve earned all of the friends I have in the world — Bertrand Russell, Eleanor Roosevelt, Dick Gregory, just as an example of them,’’ Mr. Lane says in the film. “But more than that, I’ve earned every one of my enemies, every one of them, and I’m proud of that.”