A 22-year-old Landover man was shot to death by a police officer Saturday night after being ordered several times to drop a handgun with which he had just pistol-whipped another man, Prince George's County police said.

George Larry Jones was holding a .41 magnum handgun in an apartment in the 7200 block of Landover Road when he was shot several times by Officer Christopher Shifflett, officials said. Shifflett has been placed on routine administrative leave.

Officials said the incident began when police were called about 8:45 p.m. to break up a fight in an apartment in the Sussex Street Station complex. Shifflett and another officer, who both work part time at the complex as security guards, went to the scene and broke up the fight, but returned moments later when they heard what they thought was furniture being thrown, police said.

Authorities said the officers saw Jones holding the gun by his side and a woman, later identified as Jones's mother, standing nearby with a knife. Both were ordered to disarm, but only the woman complied, police said.

The officials said Shifflett fired when Jones began to raise the gun, which later was found to be unloaded.

Maryland state law allows police officers to shoot to kill if they believe their lives, or the lives of others, are in danger. "There is no way to know when someone is holding a gun whether it is loaded," said Capt. Jimmy White, a police spokesman. "If the person has a gun and decides he's going to shoot you, there is no way you can react quicker."

Police also later discovered that Jones's mother had a knife because she was trying to prevent Jones from pistol-whipping another man with whom he had been fighting. The man, whose identity was not released, gave a statement to police and was not hospitalized, officials said.

Neighbors said yesterday that Jones's mother and a small child moved into the apartment last month. They said that Jones was often at the apartment, but that it wasn't clear whether he lived there.

Residents said that there had been frequent arguments and fights at the apartment since Jones's mother moved in.