TRIPOLI (Reuters) -- The former Libyan intelligence officer convicted of the 1988 bombing of a Pan Am flight over Lockerbie, Scotland that killed 270 people has died, his brother said on Sunday.

Abdel Basset al-Megrahi, released from a Scottish prison in 2009 and returned to Libya because he was suffering from terminal cancer, had been in and out of hospital for weeks and was taken for an emergency blood transfusion in April.

Megrahi's health had deteriorated quickly overnight, his brother Abdulhakim told Reuters. "He was surrounded by his family and died in his house," he said. He was 60.

"He was too sick to utter anything on his deathbed," Abdulhakim said. "We want people to know he was innocent."

Megrahi was found guilty in 2001 of bombing Pan Am flight 103 as it flew to New York from London on Dec. 21, 1988. All 259 people aboard the aircraft were killed and 11 people in the Scottish town of Lockerbie died from falling wreckage.

He was jailed in Scotland but sent back to Moammar Gadhafi's Libya by the Scottish authorities on compassionate grounds in 2009 because he was only expected to survive for months.

The decision angered many relatives of the victims, 189 of whom were American, and was criticized by the US administration. A number of US politicians pressed for his extradition to the United States.

Megrahi, an intelligence agent during Gadhafi's rule, was jailed in the town of Greenock in western Scotland after he was convicted for the bombing under Scottish law at a trial held in the Netherlands.

Megrahi told Reuters in October his role in the attack had been exaggerated and the truth about what really happened would emerge soon.

An intelligence agent during the rule of Gadhafi, Megrahi denied any role in suspected human rights abuses in his home country before the Libyan dictator's fall and death in a popular uprising last year.

Libya's now-ruling National Transitional Council has said it would work with the Scottish government over the possible involvement of others in the 1988 bombing, an attack the country's new rulers are eager to distance themselves from.