NASHVILLE, Tennessee (CNN) -- James Earl Ray, the confessed assassin of civil rights leader Martin Luther King Jr. who later proclaimed his innocence but never provided hard facts of an alleged conspiracy, died Thursday. He was 70.

With Ray's death, the full story of the assassination may never be revealed. Ray, who fought without success to have his name cleared, spent his last days in a coma at a Nashville hospital. He had been in and out of intensive care for more than a year with cirrhosis, a chronic liver disease.

Ray was serving a 99-year term for the assassination of King in 1968 in Memphis, Tennessee. He confessed and was sentenced, but promptly recanted and attempted to be tried on an innocent plea.

In an interview with CNN shortly after Ray's death, his attorney, William Pepper, said that although there could no longer be a trial, the Ray family and the King family will continue their efforts to uncover the truth. "The truth will ultimately exonerate James Earl Ray," Peppper said.

A high-school dropout and small-time criminal, Ray broke out of a Missouri prison in 1967 and onto the international stage on April 4, 1968. On that spring evening, King was gunned down as he stood on a balcony of the Lorraine Motel in Memphis, where he was trying to mediate a garbage workers' strike. He was struck by one bullet and died later at a hospital. The death of the civil rights leader, at age 39, prompted race riots in dozens of cities and mourning worldwide.

Prosecutors said Ray fired the fatal shot from the bathroom of a rooming house nearby. Witnesses said that moments after the shooting, they saw Ray running from the building, carrying a bundle.

Ray fled abroad and hopped from city to city. He was finally apprehended at London's Heathrow Airport on June 8. He reportedly put his head in his hands and wept when authorities confronted him. The FBI quickly identified Ray as the primary suspect. Authorities found Ray's fingerprints on the rifle, a scope and a pair of binoculars. He pleaded guilty in March 1969 and was given a 99-year prison sentence.

Ray admitted buying a rifle similar to the murder weapon and renting the room at the Memphis flophouse where the shot was fired. But soon after being sentenced, Ray began to recant his guilty plea, saying he had handed over the gun to a man he identified only as "Raoul." Over the years, Ray suggested a conspiracy and government cover-up. His 1992 book, "Who Killed Martin Luther King Jr.?: The True Story by the Alleged Assassin", offered his version of events, but investigators did not reopen the case.

Ray's father was quoted saying his son was not smart enough to have pulled off such a crime by himself. In 1978, a special congressional committee reported a "likelihood" existed that Ray did not act alone. Meantime, in 1977, Ray escaped from a Tennessee prison and led authorities on a massive manhunt over three days before being recaptured.

Ray came as close as he ever would to being absolved in King's assassination in a March 1997 meeting with one of the civil rights leader's sons, Dexter King. "I had nothing to do with shooting your father," Ray told King. Later, King asked Ray directly, "I want to ask for the record: did you kill my father?" "No, I didn't, no, no," Ray said.

"I believe you, and my family believes you, and we will do everything in our power to see you prevail," King replied.

The King family joined Ray's relatives and others in the call for a trial, saying it would be the only way to discover the full truth about what happened in Memphis.

"If James Earl Ray confesses to the public that he has more information and more people, there will be a trial," the Rev. Jesse Jackson said in July 1997. Jackson was on the Memphis motel balcony with King and witnessed the assassination.

"If he cannot get beyond the mysterious figure called 'Raoul,' he does not warrant another trial."

At the urging of Ray's attorneys, new forensic tests were conducted in 1997 on the rifle believed to have been used to kill King.

But as with earlier rounds of tests, they were found to be inconclusive -- not unlike Ray's own account of the events that placed him at the center of a controversial chapter of U.S. history.