Efram "the Spaniard" Gonzalez was a Basque ETA bomb-maker who was associated with the Medellin Cartel of Colombia during the late 1980s. He was the man who built the bombs used in the assassinations of Prime Minister Luis Carrero Blanco and Minister of Defense Alejandro Rivera and the bombing of Avianca Flight 203.
Efram Gonzalez was born in Madrid, Spain, the son of Admiral Antonio Gonzalez Villamil. Gonzalez was of Basque descent. He studied in several high schools and a boarding school in Bogota, Colombia, where he graduated as a Bachelor. At some point in his early years, he became a member of the ETA separatist group in the Basque Country, and he made a career for himself by making bombs; he made the bombs used in the assassinations of Prime Minister Luis Carrero Blanco and Minister of Defense Alejandro Rivera. During the late 1980s, he formed a connection with the Medellin Cartel in Colombia, offering to sell them bombs as well as buying 5,000 kilograms of cocaine in 1989 to sell in Europe for a large price. Gonzalez made the bomb used in the bombing of Avianca Flight 203 in 1989 in an attempt to assassinate presidential candidate Cesar Gaviria, but Gaviria never boarded the plane, as the DEA warned him about a plot against his life. Gonzalez's bomb killed 110 innocent people in the ensuing suicide bombing, carried out by Jaime Carrera.