The suspected Monterey Park attacker was 72. Here's why older shooters are rare

Investigators work at the scene of a mass shooting in Monterey Park, California, on Sunday. A 72-year-old suspect was found dead with a self-inflicted gunshot wound inside a white van in Torrance, Calif. (Robyn Beck/AFP via Getty Images)

Police are still investigating a motive behind an attack in Monterey Park, Calif., this weekend that left 11 dead.

The suspected shooter, a man named Huu Can Tran, was found dead with a self-inflicted gunshot wound after a manhunt on Sunday, authorities said.