Accusations of civilian killings and other scandals have eroded confidence in the very institution that is the linchpin of President Alvaro Uribe's mission to make this notoriously violent country safer -- Colombia's US-bankrolled army.
Doubts were bolstered on Friday when two imprisoned rebels phoned a radio station and described how army intelligence officers allegedly paid ex-guerrillas thousands of dollars to stage phony bombings ahead of Uribe's August swearing-in for a second term.
The jailed guerrillas alleged that the officers intended to take credit -- and to claim reward money -- for discovering and defusing the bombs, one of which killed a passer-by and wounded 19 soldiers.
"The officers offered 30 million pesos (US$12,500) for each attack and they paid those who could make one happen,'' an ex-guerrilla known as Evaristo said from the La Picota prison.
They also said that the intelligence officers paid ex-guerrillas to organize the bogus surrender of a rebel unit and then to falsely accuse peasants in the area of being rebel fighters.
Colombia's army chief and defense minister acknowledged late last month that such a plot was being investigated.
But the guerrillas' claims were just the latest black eye for the military amid a string of scandals that have tried the patience of many ordinary Colombians, human rights groups and even some lawmakers in Washington.
"So many of these cases have come to light in recent months, they have planted doubts about all the actions of the armed forces,'' said Marco Romero, director of the human rights group Codhes.
Of particular concern are complaints that people with no history of guerrilla ties have been seized by security forces only to turn up dead, identified by the army as rebels.
Last month alone, the chief federal prosecutor's office opened investigations of 14 soldiers for allegedly killing civilians and claiming they were guerrillas.
No one keeps national figures on so-called extrajudicial killings.
But between 2002 and last year, the independent activist group Judicial Freedom Corp recorded 107 such cases in just five municipalities in the northwestern state of Antioquia.
"There's a pressure on these army units to produce results, to be the most active in killing guerrillas," Elkin Ramirez, a lawyer for Judicial Freedom Corp, said.
"This comes right from the top, from the presidency," he added.
Uribe has tied his political fortunes to a get-tough approach to crime and violence in Colombia
Colombians credit his initiatives for a sharp drop in high kidnapping and murder rates, and reelected him by a wide margin in May.
The high-performing Antioquia-based 4th Brigade reported eliminating 705 "hostiles" last year, a figure combining rebels and right-wing paramilitaries killed, captured or surrendered.
But rights activists say that number is inflated by extrajudicial civilian killings.
They point to the case of Luz Morales, a 16-year-old girl, who was detained in 2003 by 4th Brigade soldiers on suspicion of belonging to the Revolutionary Armed Forces of Colombia, or FARC.
The next day, the army said the girl had escaped custody and mounted an attack on the unit in which she alone was killed.
"We know this is not true, my sister had nothing to do with the guerrillas," said Blanca Morales, Luz's sister.
A 4th Brigade spokesman declined to comment, and the Defense Ministry refused repeated requests to discuss cases of alleged extrajudicial killings.