LAX Was Target of Bomb Plot

May 29 -- Ahmed Ressam, an Algerian convicted of terrorism last month for trying to bring a carload of explosives into the United States from Canada, is now cooperating with American investigators.

ABCNEWS has learned Ressam is now providing investigators details of an international conspiracy to bomb Los Angeles International Airport.

The plot was designed to kill thousands of people by detonating three powerful bombs, set with timing devices.

Investigators recreated one of the explosives by matching Ressam's ingredients.

Sources say Ressam has told investigators his orders came from a senior aide to Osama bin Laden in Europe.

Authorities already knew that in 1988 Ressam attended a terrorist training camp in Afghanistan sponsored by bin Laden.

The plan unraveled when Ressam, an Algerian national, was caught crossing the border into Washington state with a carload of sophisticated explosives.

It was thought millennium celebrations were the target, which prompted Seattle to cancel its New Year's Eve festivities at the Space Needle.

Now, following his terrorism conviction, Ressam has done what experts say few Islamic terrorists have ever done: cooperate with U.S. investigators.

"I think there's a great motivation for a person in this position to save themselves," says Robert Blitzer, a retired FBI counter terrorism chief.

And in doing so, Ressam is now expected to become a government witness in other cases. He now faces a 140-year prison sentence. How much of a break he gets will depend on how much he helps.