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Key events since the Lockerbie bombing:

Dec. 21, 1988—Pan Am Flight 103 from London to New York is destroyed over Lockerbie, Scotland, by plastic explosives hidden in a radio cassette player in the baggage compartment. All 259 passengers and crew are killed, as are 11 people on the ground.

May 1990—The Presidential Commission on Aviation Security and Terrorism, formed after the bombing, recommends a top-to-bottom overhaul of the U.S. aviation security system.

July 1990—The United Kingdom’s Air Accidents Investigation Branch releases its formal investigation on the bombing, recommending that aircraft manufacturers study measures to mitigate the effects of a midair explosion.

November 1991—Two Libyan intelligence operatives are indicted for planting the bomb at an airport in Malta. But Libyan leader Moammar al-Gadhafi refuses to turn over the suspects.

April 1999—After years of negotiations and sanctions against Libya, the suspects are turned over for trial.

January 2001—One of the Libyan intelligence agents, Abdel Basset Ali al-Megrahi, is convicted of the bombing and sentenced to life in prison. A co-defendant was acquitted.

December 2002—After the installation of hundreds of explosives detection machines, 100 percent of checked bags are screened for explosives as a result of a congressional mandate passed after 9/11.

June 2007—A Scottish appeals commission rules that al-Megrahi “may have suffered a miscarriage of justice” and should be granted a new appeal.

November 2008—Families of the 180 American victims of Pan Am 103 receive final compensation from the Libyan government.

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