A retired general who was convicted and later cleared of aiding one of Mexico's most powerful drug lords has been shot and killed in the capital.
Former Brigadier-General Mario Arturo Acosta Chaparro was attacked on Friday while at a garage in the Anahuac neighbourhood and died at a hospital, according to Mexico City Attorney-General Jesus Rodriguez Almeida.
Witnesses told police that Acosta had just arrived at the garage to drop off a car when a lone gunman approached and shot him three times in the head, Rodriguez said.
The assailant, who used a 9mm handgun, got away on a waiting motorcycle driven by an accomplice.
In 2010 Acosta survived an attack in which he was shot in the abdomen in the Mexico City neighbourhood of La Roma.
Acosta was jailed in 2000 on charges of protecting Amado Carillo Fuentes, a leader of the Juarez drug cartel who had died three years earlier after botched plastic surgery.
But in 2007 a panel of judges overturned Acosta's drug trafficking conviction and ordered his release, ruling that prosecutors had failed to prove the alleged links to Carillo Fuentes.
In 2002, Acosta was accused of homicide in the disappearance of leftist activists and revolutionaries during the government's "dirty war" against dissidents during the 1970s and 1980s. A judge determined Acosta was not responsible for the disappearances and the charges were dismissed.