The search for the truth behind the Lockerbie bombing is unlikely to end with the death of Abdelbaset Ali Mohmed al Megrahi.

Figures in the former Libyan regime of Colonel Gaddafi that took responsibility for the atrocity have survived the turmoil of the dictator's overthrow.

At some point, prosecutors, whether Libyan or Scottish, may elicit key information from those close to events in 1988.

Foremost is Saif al Islam Gaddafi, the dictator's son, once seen as Colonel Gaddafi's heir apparent as leader of Libya.

Since he was taken prisoner by rebels in November last year in the southern Libyan town of Obari, Saif al Islam has been held captive.

Last month the Hague demanded that Libya's National Transitional Council hand him over to be tried for war crimes allegedly committed during the civil war. The NTC said it wanted to try him in Libya. In 2008 Saif al Islam said Libya had admitted responsibility, but not guilt, for the Lockerbie bombing simply to have trade sanctions lifted.

Another figure who may hold clues is Moussa Koussa, the former Gaddafi ally and confidante and Libya's one-time foreign intelligence chief who defected during last year's civil war. He fled via Tunisia and is now believed to be hiding out in the Middle East. He was a Libyan intelligence agent at the time of the 1988 atrocity.

Former Libyan intelligence chief Abdullah al Senussi, a close advisor to Saif al Islam and one of Col Gaddafi's closest aides, is also believed to hold vital information that could help establish the full facts about the Lockerbie bombing.