A sting operation run by a Northern Virginia law enforcement task force has resulted in the seizure of 118 pounds of pure heroin and cocaine in Colombia and the arrest there of two men who had intended to ship the drugs to Virginia, authorities said yesterday.

The seizure was probably the largest for a Virginia-based drug case, according to Capt. Gary M. Jenkins of the Virginia State Police. The state police and agents from the Drug Enforcement Administration led the investigation as part of a regional task force with local police departments and federal agencies.

The investigation targeted Tito Arenas-Cristancho, 45, of Cucata, Colombia, who police believe had been a major drug supplier since 1986, Jenkins said. The year-long probe eventually resulted in an agreement by Arenas-Cristancho, also known as Luis Chacon, to sell the drugs to undercover agents.

The agents agreed to pay $3.1 million for them, although Jenkins said that payment was not made. Typically, Jenkins said, drug shipments go from Colombia to New York and then filter down to Virginia. But in this case, the cache was to go to Virginia first, Jenkins said.

In late May, state police and DEA agents seized the bricks of heroin and cocaine, wrapped in duct tape, at a South American airport. Arenas-Cristancho was arrested May 31 by Colombian national police and American agents near the border with Venezuela. Another man, Hernando Cely-Lozano, 47, who was allegedly a lieutenant in Arenas-Cristancho's organization, was arrested the same day in Bogota.

The two men have not yet been extradited back to this country. They will be prosecuted in U.S. District Court in Alexandria, where they are facing charges of conspiracy to import heroin and cocaine and distribution of heroin and cocaine.

"We knew that these drugs were destined for New York and other northeast cities by way of Virginia," said Terry Parham, DEA assistant special agent in charge of the Washington field office, "and believe we have choked off a key heroin and cocaine smuggling route."

Jenkins said that by pooling state, local and federal resources, investigators "were able to successfully retrace and dismantle an entire drug supply chain all the way back to its international source."