The FBI doesn't have enough evidence to seek an indictment despite the CIA's conclusion that Iran was responsible for last year's bombing of Pan Am Flight 103 over Scotland, The Washington Post reported in Thursday's editions.

A CIA assessment of the Dec. 21, 1988, bombing has concluded that Iran hired a Syrian-based Palestinian organization to carry out the operation, sources told The Post.They said the FBI is investigating the possibility that one of two American college students who had Arab boyfriends may have been the unsuspecting courier who carried the bomb onto the flight.

The explosion over Lockerbie, Scotland, killed 270 people. The flight had originated in Frankfurt, West Germany, and stopped in London before heading to New York.

The CIA is confident of its conclusions blaming Iran, but the FBI doesn't believe sufficient evidence exists to seek indictments against the Popular Front for the Liberation of Palestine-General Command, the newspaper said.

The organization is headed by Ahmed Jibril, who with his senior aides met at least once last fall with Iranian officials in Tehran, the Post reported. Published reports previously have linked Jibril's organization to the bombing.

Jibril has denied that his organization planted the bomb but acknowledged in an ABC News interview broadcast last Friday that his group routinely used the same kind of explosive device that investigators say blew up the Pan Am jumbo jet.

Jibril's first lieutenant, Hafez Dalkamoni, who Jabril said commonly built and used the bombs, is jailed in Germany after a police raid last October that netted weapons and three bomb devices like the one used to blow up Flight 103.

Jibril has denied that his group receives money from Iran but has said he shared Iran's outrage at how the United States last year shot down an Iran civilian passenger plane.