Judges have ruled that relatives of people killed in the 1988 bombing of a Pan Am jet over Lockerbie, Scotland cannot launch an appeal on behalf of the only man convicted of the attack.

In an unusual case, relatives sought to appeal on behalf of the late Abdel Baset al-Megrahi, a former Libyan intelligence officer.

Some of the victims' families believe al-Megrahi was not responsible for the bomb that exploded aboard a New York-bound Boeing 747 in 1988, killing 270 people.

Usually only a convict's executors or family can mount a posthumous appeal, and judges in Edinburgh ruled Friday that the law does not "allow victims or relatives of victims to be direct participants in criminal proceedings."

Al-Megrahi was released from prison in 2009 and died in Libya in 2012.