OCEANSIDE, Calif. -- Police are investigating what prompted a man to fatally stab a 54-year-old woman from northern California who was walking to her car in an Oceanside shopping center parking, Oceanside officials said Saturday.

Oceanside police investigators have a 35-year-old man in custody and are investigating why Katherine Parker -- a northern California resident who was visiting family in the area with her husband -- was slain, said Officer Kim Rainwater.

About 4 p.m. Friday, Parker was walking to her car from the Hallmark store in the 2400 block of Vista Way when she was assaulted, Rainwater said.

The suspect, Russell Andreasen of Oceanside, remained at the scene and waited for police to arrive, Rainwater said. He was arrested without incident and taken to Oceanside's police station.

Medics airlifted the victim to Scripps Memorial Hospital La Jolla, where she was declared dead just after arrival, according to the medical examiner's office.

Parker was a resident of Lincoln, a small town in the Sierra Nevada foothills, about 25 miles northeast of Sacramento.