According to Human Rights Watch, the Fourth Brigade, under Ospina's command, worked alongside the deathsquads controlled by the paramilitary leader Carlos Castaño. In a report published three years ago, itsummarises the results of an investigation carried out by the Attorney General's office in Colombia. OnOctober 25th 1997, a force composed of Ospina's regulars and Castaño's paramilitaries surrounded a villagecalled El Aro, in a region considered sympathetic to the country's left-wing guerillas. The soldiers cordonedoff the village while Castaño's men moved in. They captured a shopkeeper, tied him to a tree, gouged out hiseyes, cut off his tongue and castrated him. The other residents tried to flee, but were turned back byOspina's troops. The paramilitaries then mutilated and beheaded eleven of the villagers, including threechildren, burned the church, the pharmacy and most of the houses and smashed the water pipes. When they left,they took 30 people with them, who are now listed among Colombia's disappeared.