(Reuters) - Investigators collected 42 bullet casings from the scene of one of California's bloodiest mass shootings as they sought clues on Monday to what drove an elderly gunman to open fire in a dance hall he had frequented, killing 11 people, before taking his own life.

Police identified Huu Can Tran, 72, as the lone suspect in a massacre that unfolded Saturday night in the midst of a Chinese Lunar New Year celebration in the town of Monterey Park, a hub of the Asian-American community just east of downtown Los Angeles.

Authorities said he drove to another dance hall where a second, would-be attack was thwarted and later shot himself to death in his parked getaway vehicle as police closed in to make an arrest on Sunday, ending an intense manhunt some 12 hours after the rampage.

Ten people were killed and 10 others wounded when Tran opened fire at the Star Ballroom Dance Studio, a venue popular with older patrons of Asian descent, then drove off. One of the victims hospitalized in critical condition died of his wounds on Monday, Monterey Park Police Chief Scott Wiese told reporters.

All of the dead, six women and five men, were in their 50s, 60s and 70s, the coroner's office said.

Even as Los Angeles-area police worked through a second full day of their investigation, seven people were reported slain in a separate, mass shooting in the northern California coastal town of Half Moon May on Monday. read more

In another incident, one person died and seven were injured in Oakland, near San Francisco, in a shooting between several individuals, Oakland Police Department reported.

At a news briefing on Monday, Hilda Solis, a member of the Los Angeles County Board of Supervisors, called Saturday's Monterey Park gun violence the deadliest mass shooting on record in Los Angeles County, the most populous in the United States and home to some 10 million residents.

About 20 minutes after the attack, Tran barged into a second dance club, the Lai Lai Ballroom & Studio in the neighboring community of Alhambra, where an employee wrestled away the intruder's semi-automatic assault-style pistol before any shots could be fired, officials said.