He was believed to be responsible for the deaths of an unknown number of people with official estimates ranging in the hundreds. US authorities currently link him to the deaths of more than 220 people, having supposedly murdered members of both his own organization the Medellín Cartel and the rival Cali Cartel, as well as police officers and government officials. Colombian authorities connect him to the deaths of more than 40 police officers.

Arrested in 1991, he is serving multiple life sentences in a US prison. He was the first person ever to be convicted under a 1956 Federal law that made bombing a civilian aircraft a crime and the 1986 terrorism statute that allows the trial of foreign citizens in the United States if at least one victim was an American citizen. Among his convicted crimes is the 1989 bombing of Avianca Flight 203, which killed 110 civilians.