A National Guardsman shot and killed a man who threw a piece of broken glass at a group on patrol and later pointed a BB gun that officers mistook for a rifle, police said.

Homicide detectives are investigating the shooting, but the guardsman, whose name was not released, appears to have acted appropriately, said Sgt. Joe Narcisse, a police spokesman.

The dead man did not carry identification, Narcisse said.

The National Guard members saw the man about 1 a.m. holding a hacksaw while riding a bicycle through the impoverished Lower Ninth Ward, which largely vacant since Hurricane Katrina. The Guard has been patrolling less populated areas of the city since June to allow the depleted police force to concentrate on areas where people have returned since the hurricane.

"As the guardsmen approached the man, he produced a knife, threatening the military men and then threw a piece of broken glass at them, cutting a sergeant's arm," Narcisse said in a news release.

The man ran into a rundown house, he said. When police and guardsmen entered the house and approached the man, he pointed a BB gun that looked like a rifle at them. A Guardsman shot the man several times, police said.