"Eyewitnesses claim the assailant smashed through several walls before killing Colombia's most notorious drug lord, Alejandro Castillo, A.K.A. El Dogo. Speculation continues as to whether this superhuman assassination was carried out by a man, monster or machine." ― Reporter
Alejando Castillo was a notorious Colombian drug lord with known ties to HYDRA. He was assassinated by Deathlok under the orders of John Garrett.
"I didn't just want to cross him off, I wanted to make a spectacle. People are killed by guns everyday in Bogotá but how often does a monster punch a drug lord's head clean off." ― John Garrett
Deathlok was sent to kill Alejandro Castillo in order to showcase his effectiveness as a super soldier, so that Ian Quinn could sell super soldiers to the U.S. government. Deathlok decapitated him. The assassination became news that was watched by Coulson's Team who tried to deduce why John Garrett would have Deathlok in Bogotá. Jemma Simmons wondered why they would kill a drug lord with ties to HYDRA.
His alias, "El Dogo", is Spanish for "Bulldog".