Updated

Two New Jersey senators are demanding that any new Libyan government agree to extradite to the United States the man convicted of the Lockerbie bombing two years after he was released from prison to die of cancer.

Abdel Baset al-Megrahi was convicted in 2001 of murdering 270 people, most of them Americans from the tri-state area, by blowing up a Pan Am plane over the Scottish town of Lockerbie on Dec. 21, 1988.

He was freed on Aug. 20, 2009, after prison doctors said he had prostate cancer and estimated he had only three months to live. He is still alive, and last month he appeared at a televised rally in Tripoli alongside Muammar Qaddafi.

“As my investigation showed, and as time has proven, al-Megrahi’s prognosis was a sham amounting to nothing more than an effort help UK business interests curry favor with the former Libyan government,” said Sen. Robert Menendez, a Democratic member of the Senate Foreign Relations Committee.

“At the time we all understood it to be a massive diplomatic blunder and an insult to the families of the victims of the Lockerbie bomber,” he said. “The fact that the Qaddafi regime is in shambles and has turned on its own people shows that undermining humanitarian principles in order to serve short term business interests is never sound policy.”

Sen. Frank Lautenberg, also a Democrat, said: “No stone should be left unturned in bringing Megrahi and everyone responsible for this heinous act—including Qaddafi—to justice. The family members of the victims who have had to suffer through watching this terrorist be set free deserve no less.”

The second anniversary of al-Megrahi's release comes as Libyan rebels gain ground in their six-month civil war against Qaddafi's Tripoli-based regime. Some politicians in Britain and the U.S. have called for al-Megrahi to be re-imprisoned if Qaddafi is overthrown.

Scottish First Minister Alex Salmond on Saturday defended the release al-Megrahi, saying the decision was made "on compassionate grounds and compassionate grounds alone" and was not influenced by economic, political or diplomatic factors.

"Whether people support or oppose the decision, it was made following the due process of Scots law, we stand by it, and al-Megrahi is dying of terminal prostate cancer," he said.

A leading cancer specialist, however, said 59-year-old al-Megrahi appeared to be receiving a cutting-edge hormone treatment and could live for several more years.

Prof. Roger Kirby, a consultant urologist at the Prostate Cancer Center in London, said doctors in Scotland would have been unaware of the new hormone-based therapy abiraterone, which was recently approved by the U.S. Food and Drug Administration and is still not available in Europe.

"He has long outlived the speculative three-month prognosis, and it appears he may continue to do so for a while yet," Kirby said. "I strongly suspect that this drug has been central to that."

Al-Megrahi, a former Libyan intelligence officer, is the only person convicted over the Lockerbie bombing, Britain's worst terrorist attack.

His release infuriated the families of many Lockerbie victims, who suspected Britain's ulterior motive was to improve relations with oil-rich Libya. Some relatives, however, believe al-Megrahi was wrongly convicted and that evidence points to Iranian-backed Palestinian militants as the perpetrators.

The Associated Press contributed to this report.