Abdelbeset Ali Mohmed al Megrahi, the only person convicted in connection with the Lockerbie airline bombing that killed 270 people, died Sunday, the Libyan government and family members said. He was 60.

The former intelligence officer, who had suffered from prostate cancer, will be buried Monday, according to a Libyan foreign ministry spokesman.

Al Megrahi's cousin, Omer al-Gharyani, told CNN he was at a Tripoli hospital with al Megrahi when he died.

His death came more than two-and-a-half years after he was freed from a life sentence in Scotland because he was said to be dying.

His brother said the family refers "to the deceased as 'the convicted innocent.'"

"May God bless his soul," he added.

Relatives of those killed in the bombing expressed relief and, in some cases, anger.

"He was a mass murderer. I feel no pity," said Susan Cohen, whose daughter was among the 189 Americans killed.

The destruction of Pan Am Flight 103 over Lockerbie, Scotland, in 1988 was the deadliest act of air terrorism targeting Americans until the September 11, 2001, attacks, according to the FBI.

American and British investigators who painstakingly pieced together the wreckage concluded it was destroyed by a bomb.

Authorities in those nations claimed al Megrahi -- once the security chief for Libyan Arab Airlines -- and Al Amin Khalifa Fhimah were Libyan intelligence agents who planted the explosive. They were charged in November 1991 on 270 counts of murder and conspiracy to murder.

That indictment set off the first battle over al Megrahi, until Libya handed him and Fhima over in the face of international pressure.

Eight years after his trial and conviction, a fresh uproar arose when he was released from a Scottish prison because he was battling terminal prostate cancer. He received a hero's welcome upon arriving home in Libya.

And last year, as rebel fighters advanced and, ultimately, toppled Moammar Gadhafi and his regime, the debate was revived as some called for al Megrahi's extradition back to Britain or to the United States. But even after new leaders took power, he remained in Libya.

CNN Senior International Correspondent Nic Robertson tracked al Megrahi down last August at the palatial villa Gadhafi had built for him.

Apparently in a coma and near death, al Megrahi's family said then that his son and mother were trying to care for him with oxygen and an intravenous drip, but with no medical assistance.

His death may make it impossible ever to get the full story behind the Lockerbie bombing.

In an interview with Reuters last October, al Megrahi vowed "new facts" would come to light. The truth will come out "one day, and hopefully in the near future," he said.

Reacting to news of the convicted killer's death, British Prime Minister David Cameron on Sunday reiterated his belief that "he should never have been released from prison."

"Today is a day to remember the 270 people who lost their lives in what was an appalling terrorist act," Cameron at the NATO summit in Chicago. "Our thoughts should be with them and their families for the suffering they've had."

Scotland's First Minister Alex Salmond -- the top Scottish political figure -- likewise expressed sympathy for the attack's victims, while asserting that al Megrahi's death puts "to rest some of the conspiracy theories which have attempted to suggest that his illness was somehow manufactured."

Despite widespread criticism, "extensive scrutiny" has found that Scotland released al Megrahi on "compassionate grounds alone," Salmond said in his statement.

His release -- and the celebrations that greeted him in Libya -- sparked condemnation from the United States and British governments, and from some victims' families.

U.S. Sen. Charles Schumer, a New York Democrat, accused "the Scottish government, perhaps with the participation of the British government, (of creating) a major injustice when they let him out."

"This man was a horrible man," Schumer told CNN on Sunday. "It would have been better had he not died in freedom, but died in prison. That's what he deserved."