A federal and local police drug task force announced the arrest of nine persons yesterday following a year-long investigation into the sale of heroin and cocaine in Washington and along the East Coast.

Eight arrests were made in Northern Virginia and one in the District of Columbia over a six-hour period yesterday. Police also said they seized more than $100,000 worth of cocaine and heroin worth about $25,000 "wholesale." They said the street value of the drugs would be much higher.

The arrests were announced by an agent of the Federal Drug Enforcement Agency and D.C. Police Chief Burtell M. Jefferson at a news conference at D.C. police headquarters.

D.C. police narcotics squad Lt. William Merritt said the cocaine traffic originated in Colombia, South America.

The drugs were brought into the Washington area through National Airport by "couriers" who concealed the drugs on their persons, the officials said. Some of the alleged couriers were pregnant women, they said.

The nine persons arrested yesterday were indicted Monday by a federal grand jury in Richmond. They were being held at Fairfax County jail last night on cash bonds ranging from $50,000 to $100,000. Each was charged with 20 counts of violating the U.S. Controlled Substances Act, police said. Several of the suspects also were charged with conspiracy to violate drug laws.

DEA agent David Cannaday and Jefferson said two of the nine persons were of "equal rank" as leaders of the alleged drug ring, which police said has dealt in millions of dollars worth of drugs. However, the police officials declined to single out the individuals.

Police said two other persons are being sought in the Washington area in connection with the case. Their names were not released. The officials said the investigation is continuting in Colombia and that more arrests are expected.

In addition to the confiscated drugs, police said they seized $12,000 in cash, four vehicles and two firearms.

The suspects were identified as:

Wayne M. Hargrove, 26, of 1101 S. Arlington Ridge Rd., Arlington; Marion T. Starr, 25, of 2801 Park Center, Alexandria; Charles H. Lott, 23, of Portland, Ore.; Antonio L. Perdiz Jr., 46, of New York; Evangelina D'Oliveira, of 5106 Columbia Pike, Arlington; Alfred D. McCoy, 41, of 1300 Army Navy Dr., Arlington; Llewyln J. Quander, of 402 East Del Ray Ave., Alexandria; Michael F. Tillery, 30, and Paulette A. Ashton, both of 1101 S. Arlington Ridge Rd., Arlington.