A violent Harlem-based drug ring, suspected of trafficking at least 2,000 pounds of marijuana a month into the city, has been dismantled with the arrests of 19 individuals, Police Commissioner Raymond Kelly said yesterday.

On the street, they were known as the Two-Mile Posse, a name that grew out of their common roots at Kingston, Jamaica.

They had a reputation for brutality and for vengeance against rival drug dealers or estranged colleagues. Now, many of the posse could face the death penalty for their alleged crimes, law enforcement sources said.

In June 2002, police said, several members of the posse hacked a man to death with machetes after the victim, Dennis Paulk, tried to rob one of their associates. Members of the group have already been charged in three murders, including that of Paulk, and police said they suspect the posse could be connected to at least four more.

“Marijuana is so often touted as a recreational and nonviolent drug,” Mr. Kelly said. “However, this case shows just how deadly it can be. The Two-Mile Posse saw the huge profit potential in this drug and exercised extreme violence to protect their illegal operation.”

An investigation into the posse began in 2003, after a string of violent murders and shootings in North Harlem piqued the interest of detectives from the city’s 32nd Precinct. Working with the Organized Crime Drug Enforcement Strike Force, a multi-agency project that draws resources from local, state, and federal policing agencies, detectives are said to have constructed a detailed picture of the hierarchy and operations of the drug ring.

With operational bases in Tuscon, Ariz., and Houston, the posse imported tons of high-grade marijuana from sources in Mexico and shipped the drugs to the Dunbar Houses in New York using delivery companies and their own cars or trucks, according to the authorities. Once a drug shipment arrived in New York, police said, the Posse divided it into bricks of between 10 and 15 pounds each, which they distributed to their wholesale network throughout the city and along the entire East Coast.

The national operation, which had been in place for at least 10 years, generated between $10 million and $15 million a year in revenue, according to police.

In making the 19 arrests, officers allegedly confiscated 4,400 pounds of marijuana, six guns, and a 2002 BMW, and found that several members of the posse were residing in the country illegally.