VIDEO: Cellphone video moments after Oakland officer-involved shooting
Police also identified the officer who fatally shot Alehegne in the 200 block of MacArthur Boulevard as Jennifer Farrell, an 18-year veteran of the department.
Oakland police didn't say where Alehegne is from or release any other information about him.
Police said that Farrell shot Alehegne because he had hit her multiple times with a metal chain when she tried to talk to him.
Police said Farrell went to a residential complex at the corner of MacArthur Boulevard and Van Buren Avenue at about 7 a.m. Thursday to follow up with the victim of an assault at the complex that had been reported a short time earlier.
Police Chief Sean Whent said on Thursday that the victim told the first officers who responded to the scene that the suspect had been trespassing in the complex's garage. When the victim asked him to leave, he assaulted her, according to Whent.
The responding officers, who were working the overnight shift, took some initial information from the victim but couldn't find the suspect and then left the area, Whent said.
Oakland police said that Farrell, who was beginning her day shift, did a follow-up interview with the victim.
Police said that as Farrell got into her patrol car and began driving away, Alehegne, who matched the victim's description of the suspect, stepped from the sidewalk onto the roadway in front of her car.
According to police, when Farrell got out of her car she was immediately assaulted by Alehegne, who began hitting her in the head and face with a chain.
Police said Alehegne continued to advance at Farrell while swinging the chain, so the officer discharged her service weapon, striking Alehegne, who was pronounced dead at the scene.
Farrell was transported to a hospital, where she was treated for trauma to the head and face, according to police. She has since been released.
In accordance with Oakland Police Department policy, the shooting is being investigated by its homicide and internal affairs division as well as by the Alameda County District Attorney's Office.
Oakland police said the incident is the sixth officer-involved shooting in their city this year and the fourth that was fatal.