A Prince George's County police officer shot a man in Capitol Heights last night, critically wounding him, officials said. It was the second police shooting in the county in as many days.

The man, whose name was not immediately released by police, was shot in the back, a source said. He was taken to Washington Hospital Center, where he was admitted in critical condition, the nursing supervisor there said.

The shooting occurred about 8 p.m. at Nova Avenue and Rail Street, said Cpl. Debbie Sabel, a Prince George's police spokeswoman. An officer was about to serve a search warrant at a house in the 1600 block of Nova Avenue when a man parked in the driveway of the home suddenly got out of his car, said Capt. Andy Ellis.

The officer "perceived a threat from the guy" and fired one round, Ellis said. It was unclear why the officer felt threatened, but police recovered a handgun from the vehicle and a substance they believed to be crack cocaine inside and outside the vehicle, Ellis said. Two people were arrested outside the house on drug charges, he said.

On Tuesday, in the department's first fatal shooting of the year, a man in Landover Hills was shot by police after he allegedly threatened his mother with a knife. Police sources said Eric Stewart, 31, was shot once in the head after he disobeyed orders to drop the knife and swore that he would kill his mother.

Last night's shooting occurred in a subdivision just across the line from the District, in a group of single-family bungalows surrounding John E. Howard Elementary School.

A longtime resident said the neighborhood has become troubled in recent years, with cars "zooming through here all night long" and an open-air drug market operating on several corners.

The Prince George's police department, which led the nation in fatal shootings per officer during the 1990s, had been close to recording a year with no fatal police shootings. Last year, police officers shot seven people, two of them fatally. Tuesday's shooting was the second by an officer this year and the first that resulted in a death.

Police Chief Gerald M. Wilson said the reduction was a result of 18 months of department-wide retraining and the introduction of less lethal weapons to the department's arsenal.