D.C. police announced yesterday that a five-month investigation has resulted in the arrest on lottery charges of three people alleged to head one of the city's biggest illegal numbers operations, thought to take in about $30,000 a day.

Warren R. Cooper, 53, of 1506 Hamilton St. NW, the alleged head of the ring, was charged Wednesday night with operating a lottery and possession of an unregistered pistol. Theodora Mae Campbell, 34, of the same address and John Samuel Matthews of 1708 Evarts St. NE were charged with operating a lottery, police said.

Cooper declined to comment last night. Matthews and Campbell could be reached for comment.

Armed with D.C. Superior Court warrants, members of the gambling squad raided 11 apartments and homes in the city Wednesday afternoon. They seized $110,000 in cash from three of those locations, and seized 3 1/2 ounces of heroin, with an estimated street value of $35,000, in a house at 1830 Fourth St. NW.

"We believe this is one of the top five illegal lottery organizations in the city," said Sgt. Carnwell Dean, of the department's gambling squad. "It's a multimillion-dollar-a-year operation."

Cooper was arrested inside the Jet Liquor store, 1018 Rhode Island Ave. NW, where he works, police said. Officers said they found a handgun at the store, leading to the weapons charge against him.

About 50 numbers writers were employed in the operation, police said.