Federal drug agents have arrested a Prince William County automobile dealer in an alleged conspiracy to ship millions of dollars worth of cocaine into Northern Virginia from New York City and Miami.

U.S. Attorney Henry E. Hudson and federal agents have charged that Robert Colon used E-Z Street Motors in Dumfries as a front to launder money from a drug distribution network that brought 12 kilograms of cocaine a month into Northern Virginia.

His arrest, along with five others, culminates an investigation of more than two years by the Drug Enforcement Administration. The investigation began when Richard Keith Johnson was arrested at National Airport on April 17, 1988, trying to smuggle cocaine in a suitcase.

Johnson, who became an informer, implicated Colon, according to an affidavit on file in U.S. District Court in Alexandria.

According to Johnson, Colon had hired him to fly to New York to bring back cocaine. At the time he was arrested, Johnson was carrying an airline ticket receipt bearing the name B. Colon, the affidavit said.

After the arrest of an alleged Prince George's County drug dealer who claimed to have ties to Colon, the probe intensified.

Federal agents, using a confidential informer, later contacted Colon, according to court records. At a meeting on July 31, 1989, Colon allegedly told a DEA agent that he had been in the cocaine business for 11 years.

Colon was charged this week with conspiracy to distribute more than five kilograms of cocaine and possession of cocaine with the intent to distribute.

Arrested on the same charges were Colon's ex-wife, Olga Colon; his current wife, Lovina Young; Bernard Duplessis, who works in Woodbridge; Luis Ensuncho, of New York; and Joseph Gonzales, of Miami. If convicted, they each face up to 20 years in prison and a fine of $4 million, Assistant U.S. Attorney John Rowley said.

Olga Colon and Duplessis were ordered held without bond yesterday.