Unarmed Youth, 17, Killed By L.A. Police : Shooting: Two plainclothes officers fire 18 times at boy. They say they thought he was hiding a gun in his sweat shirt.

Los Angeles police shot and killed an unarmed 17-year-old boy, who the officers believed was hiding a gun in a sweat shirt wrapped around his hands, police said Thursday.

Two plainclothes officers, members of the LAPD’s anti-gang unit, fired 18 shots during the Halloween night shooting in front of a convent in the 2600 block of South Hoover Street.

The coroner’s office identified the dead youth as Julio Moran of Los Angeles.

Although police said gang activity prompted the officers’ encounter with Moran, they did not know if he was affiliated with a gang. Also, it was not immediately known how many of the officers’ bullets hit Moran or where he was wounded, Officer Don Lawrence said.

Moran was shot on a sidewalk in front of a convent next to St. Joseph’s Residence, a girl’s dormitory for USC students.

Frightened nuns fled to the second floor of the convent after they heard the gunfire, Sister Ninfa Briones said.

“We were in our convent and the sound was like a machine gun--dat, dat, dat, dat,” Briones said. “One sister threw herself on the floor. She said ‘They are right out our window.’ I said, ‘Sister, turn the light off.’ ”

Scott Fisher, a junior at USC who lives in a nearby apartment complex, said he went outside after hearing what sounded like firecrackers. Across the street from the shooting, he saw eight or nine children who were trick-or-treating take cover inside a bus-stop shelter.

“When I came out they were running to the stop,” Fisher said.

Police said Officers Donald Williams and David Rosenberg were driving on Hoover Street at about 8 p.m. when they saw two young men crossing the street. The officers observed the two use their hands to signal their gang affiliation to the occupants of a gray Chevrolet that was stopped for a red light, police said.

Moran jumped out of the car, police said, and then reached back into the vehicle to retrieve a sweat shirt. When he wrapped the garment around his right hand, the officers thought he was trying to conceal a weapon, police said.

Moran then grasped the garment with his other hand, extended both arms in front of him and ran toward the two who had flashed their gang affiliation, police said. Believing he had a weapon and was about to commit an assault, the officers made a U-turn and stopped their car near Moran.

After identifying themselves, Williams and Rosenberg ordered Moran to drop what they believed was a weapon, police said.

Moran, his arms still extended with the sweat shirt covering his hands, began moving toward the officers, who thought he was about to shoot at them, police said.

Rosenberg then fired 13 rounds from his 9-mm semiautomatic pistol at Moran, while Williams fired five, police said.

Moran was taken to County-USC Medical Center, where he died. Police later determined that Moran was unarmed at the time of the shooting.