Three decades after Alas Chiricanas Flight 901 went down, the U.S. State Department is offering a reward of up to $5 million for information leading to the arrest of any individual who abetted the bombing.

On July 19, 1994, AC Flight 901 was traveling to Panama City, Panama, when a bomb on board detonated shortly after takeoff from France Field in Colón, Panama. The explosion caused the aircraft to crash in a remote jungle approximately 10 miles from the airport. All 21 passengers, including three U.S. citizens, were killed.

Evidence at the time suggested that a bomb concealed in a radio carried by a passenger identified as Ali Hawa Jamal caused the explosion. Jamal’s identity, a Middle Eastern man with links to Hezbollah, fueled theories that the attack was in revenge for the 1992 assassination of Hezbollah’s secretary-general Abbas al-Musawi, and potentially connected to the Argentine AMIA bombing that occurred just one day earlier.

The bombing of AC 901 occurred one day after a vehicle-borne improvised explosive device was detonated at the Argentine Jewish Mutual Aid Society building in Buenos Aires, Argentina, killing 85 people and injuring 300. A group calling itself Ansar Allah, which the U.S. government has determined is an alias for Hezbollah, issued a statement in Lebanon a few days later claiming responsibility for both attacks.

FBI and Panamanian authorities have since reopened the investigation multiple times, with recent findings identifying Ali Hage Zaki Jalil, another Lebanese national, as a person of interest. Jalil had been in Panama with illegal arms and detonation equipment but was ultimately released.