More than 20,000 counterfeit $20 bills seized in a Fairfax County drug raid Thursday night apparently were to be shipped out of the country to be used to buy drugs from dealers in Colombia, a federal agent said yesterday.

Authorities said the money, which they described as "not a good copy" but "good enough to pass, was going to be used in dealing with U.S. currency.

Fairfax County police and agents of the federal Drug Enforcement Agency seized counterfiet bills with a total face value of $410,400 in the drug raid at 9015 Andromeda Dr., in the Burke area.

Charles L. Gittens, special agent in charge of the U.S. Secret Service Washington field office,describe the counterfeit money as "a fairly large cache" and said there was enough paper and ink available to print $2.5 million in bogus money.

He said the investigators were surprised to find the counterfeiting operation, but believe that none of the counterfeit money had been circulated.

Gittens said he confiscated bills could have been run off in a single day on the multilith press that was found in the garage of the three bedroom home.

Gittens said the confiscated bills could have been run off in a single day on the multilith press that was found in the garage of the three bedroom home.

Gittens said the countefeit bills "would pass under certain circumstances." Hoever, he said there were distinct differences between the counterfeit and genuin bills.

"In the genuine bill, there is overall clarity," he said. ". . . overall appearance is clear, well defined."

However, he said, "On the counterfeit, the lines are fuzzy . . . Not clear at all."

Also, he said counterfeit bills lack the red and blue fibers embedded in the genuin bills.

In addition to the counterfeit bills, police said they confiscated $200,000 worth of cocaine and small amounts of heroin and marijuana.

Three of the four persons arrested during the raid appeared yesterday in U.S. District Court in Alexandra.

Virgil H. Jewell, 49, an escapee from federal prison at McNeil Island, Wash., was formally charged with counterfeiting and ordered held at the Arlington County jail wothout bond.

Robert Stanley Horning, 32, was charged with counterfeiting and held at the Arlington jail under a $50,000 bomd.

Jen R. martinez, 22, was charged with harboring and concealing and escaped federal prisoner and placed un der $7,500 bond.

Charges against a fouth person, Vicky Balding, 28, who was arrested in the drug raid, were dropped because of insufficient evidence. Police said all four lived at the Andromeda Drive address.

A U.S. attorney said the investigation is continuing.