Samos was shot by an officer during the arrest and was transported to a hospital in stable condition, Rayner said. Further details of the arrest weren't immediately known Sunday night.
Samos allegedly sexually assaulted his ex-girlfriend Saturday afternoon at a South Los Angeles home and then took the woman, her 11-year-old daughter and her 6-year-old niece to a gas station, according to police Lt. Faryl Fletcher.
There he allegedly shot a 24-year-old motorist in the back when she resisted his alleged attempt to carjack her vehicle, Fletcher said.
During the shooting, the ex-girlfriend ran away and the man fled with the two children, Fletcher said.
Samos later met his mother at a Long Beach liquor store, taking her Toyota along with his own 1- and 5-year-old sons, officials said.
Samos had contacted authorities from an undisclosed location and offered to trade at least some of the children for his ex-girlfriend, Fletcher said.
The woman shot at the gas station was hospitalized in critical but stable condition and was expected to survive, officials said.