A 32-year-old Washington man who was convicted seven years ago of operating a multimillion-dollar cocaine ring out of a posh Arlington condominium was indicted yesterday by a federal grand jury here on new drug charges after federal agents found seven pounds of cocaine in a shoulder bag.

William M. Hargrove of 909 Longfellow St. NW was charged with possession of cocaine with intent to distribute. Court papers said the estimated street value of the cocaine was $1.5 million.

Hargrove, who was free on $10,000 bond after being indicted in U.S. District Court here in December on charges of possession of heroin and cocaine with intent to distribute, was arrested by federal drug agents Monday after he left an apartment building in the 1300 block of 20th Street NW, according to court papers.

They said agents of the Drug Enforcement Administration recognized Hargrove, who also was convicted in 1980 in Detroit for interstate travel in aid of racketeering, as he left the building carrying a brown shoulder bag. When Hargrove apparently recognized the agents, according to the papers, he began acting suspiciously, walked into a nearby alley and was seen leaving the alley without the shoulder bag.

Hargrove was sentenced to 10 years in prison in 1979 for his role in a cocaine ring that operated out of the Representative condominium in Arlington. As a part of that investigation, more than six pounds of cocaine with an estimated street value of more than $1 million were seized from Hargrove's home in the District.

If convicted, Hargrove could be sentenced to 40 years in prison and fined $500,000. He is being held without bond.