TRIPOLI, Libya – He was the embodiment of one of modern Libya’s darkest chapters — a man synonymous with horrifying scenes of wreckage, broken families and a plane that fell out of the sky a generation ago. His name, Abdel Baset al-Megrahi, was little known compared to the single word that his deeds represented: Lockerbie.

Seven months after his patron dictator Moammar Gadhafi was slain in a revolution that began a new chapter for his homeland, al-Megrahi died Sunday of cancer, leaving behind countless unanswered questions about the midair attack in 1988 that blew up Pan Am flight 103 over Scotland. All 259 people on board — mostly Americans — and 11 on the ground were killed.

“I am an innocent man,” al-Megrahi insisted, most recently in his final interview in December, in the final stages of prostate cancer. “I am about to die and I ask now to be left in peace with my family.”

But his death at age 60 leaves no peace for families who still question his guilt and whether others in one of history’s deadliest terror attacks went unpunished. Scotland’s government said it would continue to investigate the bombing even after al-Megrahi’s death.

“He holds the key to what actually took place in Pan Am 103,” said Bert Ammerman, whose brother was killed in the bombing. “He knows what other individuals were involved and, more importantly, what other countries were involved.”

His attorneys had argued that the Libyan intelligence officer was scapegoated to protect the real culprits: Palestinians acting on the behest of Iran.

Al-Megrahi’s death comes about three years after Scottish authorities released him on humanitarian grounds, to the outrage of victims’ relatives. At the time, doctors predicted he had only three months to live after he was diagnosed with prostate cancer.

Anger over his release was further stoked by the hero’s welcome he received on his arrival in Libya — and by subsequent accusations that London had sought his release to protect business interests in oil-rich Libya. Britain and Scotland denied the allegations.

In the months ahead of his release, Tripoli put pressure on Britain, warning that if the ailing al-Megrahi died in a Scottish prison, all British commercial activity in Libya would be cut off, according to leaked U.S. diplomatic memos. The Libyans even implied “that the welfare of U.K. diplomats and citizens in Libya would be at risk,” the memos say.

Al-Megrahi kept a strict silence after his return, living in the family villa surrounded by high walls in a posh Tripoli neighborhood. Libyan authorities sealed him off from public access, and on Sunday scores of fellow clan members surrounded his residence to keep the media away.

Al-Megrahi’s son, Khaled al-Megrahi, confirmed that he died in Tripoli in a telephone interview but hung up before giving more details.