A drug-trafficking paramilitary group killed 10 peasants on a farm in northern Colombia in the country's worst massacre in more than three years, authorities said Thursday.
Three gunmen from a group known as "Los Rastrojos," The Scraps, stormed the farm in Antioquia state on Wednesday and apparently demanded an extortion payment.
Gen. Humberto Guatibonza, commander of the police anti-kidnapping unit, said authorities believe the Rastrojos killed the nine men and one woman when they didn't pay the money. He said a dozen detectives were investigating the crime.
The owner of the farm in the municipality of Santa Rosa de Osos, about 275 kilometers (170 miles) northeast of the capital of Bogota, was apparently being extorted by the paramilitary group, local officials said.
Antioquia police Gen. David Guzman said the gunmen arrived when the workers were finishing up their day picking fruit. When workers said they didn't know anything about an extortion payment, the gunmen opened fire and tossed a grenade at them, he said.
"This case has shocked us for the barbaric, brutal way that they murdered these completely innocent people," said Guzman.
An Associated Press photographer who saw the 10 bodies being removed from the farm said the white walls of the main house were pock-marked by bullets and the floor was splattered with blood.
At least 150 farm laborers gathered at the main square in Santa Rosa de Osos fearing new attacks, he said.
It was the first major massacre in Colombia since August 2009, when 12 members of the Awa indigenous tribe were killed in southwestern Narino state. At the time, a prosecutor investigating the case said the killings had been committed by Los Rastrojos.
The group is a violent offshoot of the Norte del Valle cartel involved in drug trafficking, extortion and murder as it competes with other criminal bands that grew out of the far-right militias known as paramilitaries.
Colombian police say the gang, which is thought to have hundreds of members, operates on Colombia's Pacific coast and along the border with Venezuela.
Several leaders of the Rastrojos were captured last week in the area and officials are blaming the group for the latest bloodshed.
The victim's family members declined to talk to the press because they feared for their lives.
Francisco Jair Lopera, mayor of Santa Rosa de Osos, called the massacre a source of national shame.
Officials have arrested about 2,600 extortionists so far this year, said Guatibonza, the commander of the police anti-kidnapping unit. About 60 percent of them are common criminals and the rest belong to guerrilla groups or organized criminal gangs.
In a radio interview, Defense Minister Juan Carlos Pinzon vowed to go after the killers.
"It's the typical barbaric act without explanation," Pinzon said. "It deserves our full attention and our resolve."