SACRAMENTO — Relatives, activists, and Sacramento officials are questioning why police shot at an unarmed black man 20 times, killing him, when he turned out to be holding only a cellphone in his grandparents’ backyard.

Relatives have identified the man as Stephan Alonzo Clark, 22, according to The Sacramento Bee. His fiancee, Salena Manni, the mother of his sons, ages 1 and 3, said his first name was Stephon.

‘‘We’re mourning right now and so we need our time to mourn,’’ she said Wednesday.

Police said the man was spotted breaking at least three vehicle windows Sunday night. Sheriff’s deputies in a helicopter said they saw him break a neighbor’s sliding glass door.

Two arriving officers chased him into the backyard of his grandparents’ home, where he was staying.

The department said he refused orders to stop and show his hands. He advanced toward the officers holding an object extended in front of him, the department said. The officers thought he was pointing a handgun and opened fire, fearing for their safety, the department said.

No gun was found and only the cellphone was near his body when more officers arrived and approached him about five minutes after the shooting, the department said.

‘‘He was at the wrong place at the wrong time in his own backyard?’’ Clark’s grandmother, Sequita Thompson, told The Bee. ‘‘C’mon now, they didn’t have to do that.’’

The department could not say how many times Clark was hit. The department said the two officers have been with Sacramento police for two and four years.

Black Lives Matter Sacramento called it a police murder and wants quick answers.

The department is required to release video from the helicopter and the officers’ body cameras within 30 days.

associated press