The suspect was identified as Enrique Acosta, 41, of Whittier. Some time after the shooting he was located in the Barstow area and taken into custody without incident. He was brought back to the Whittier jail to be booked for murder and is being held on $1 million bail.
The shooting was reported around 5:30 p.m. Tuesday at the Whittwood Town Center. Police said a woman was killed and the suspect fled the scene.
Acosta's relation to the victim and motive were not immediately disclosed but police initially described the shooting as the possible result of a domestic dispute.
Witnesses said the victim was checking out near a register with a child as the store was full of holiday shoppers when she got into an argument with a man. The shooter was heard saying something to the young boy along the lines of "I just shot your mom and now I'm leaving."