D.C. police arrested the wrong man in the Dec. 1 shooting of an undercover narcotics officer and are now looking for a suspect from New York who they say critically wounded the officer, a police spokesman said yesterday.

Officer Herman Keels was shot in the abdomen while trying to arrest a drug trafficking suspect at the Paradise Manor apartment complex in Northeast Washington. He is still in a hospital listed in serious condition.

Shortly after the shooting, police arrested Antoine Warren, 17, of the Bronx, N.Y., and charged him as an adult with assault with intent to commit murder while armed.

Police say that Warren was involved in the shooting but was not the person who shot Keels. According to a revised statement of facts prepared by the U.S. attorney's office, Warren sold a packet of crack to another undercover officer, who broadcast a lookout for Warren on the police radio.

The statement said that Warren had told police he sold the drugs, but had said that an accomplice did the shooting. An arrest warrant has been issued for Michael McGeachy, the spokesman said.

The mistake occurred because Warren and McGeachy were dressed virtually the same, the spokesman said. Detective Joseph Schwartz testified at Warren's preliminary hearing on Tuesday that police had interviewed witnesses of the shooting who verified Warren's account.

After the hearing, charges against Warren were dismissed, and he was transferred to the Superior Court's juvenile division, where he was charged with drug trafficking and aiding and abetting the shooting, sources said. Juvenile cases are not open to the public.