A man suspected of killing three homeless people in a matter of days is already in custody over a separate fatal shooting, Los Angeles police have said.
A father-of-two was shot dead during that incident on Tuesday, and Powell was detained on Thursday.
Powell has now been named as the chief suspect in the killings of three homeless men between 26 and 29 November.
LA police chief Michel Moore said a car identified as being driven by the suspect in those shootings had been matched with the vehicle Powell was driving on Tuesday, which was seen in security footage.
A handgun found in that car also matched the weapon used in the homeless killings, which happened in different locations across two large areas of the city.
Mr Moore said one was killed “brutally and ruthlessly” as he was sleeping on a sofa, one was leaning against a wall, while the third was sleeping on a pavement.
Police have not named the victims, but the Los Angeles Times reported they were Jose Bolanos, 37, Mark Diggs, 62, and an unidentified 52-year-old man.
The victim in Tuesday’s shooting in San Dimas has been named as Nicholas Simbolon.
The 42-year-old was found dead in his garage, said police, who believe he was followed to his home from an electric vehicle charging station and robbed.
A motive has not been established for any of the killings.