Christopher Dorner is believed to have tracked at least five LAPD officials and their families in the weeks before he began his series of killings.
Dorner, 33 reportedly staked out the homes of those officers he held responsible for his 2009 dismissal from the force.
LAPD Captain Phil Tingirides told the Los Angeles Times that his neighbour had seen a pick-up truck circling his area days before Dorner’s first murder. The driver matched Dorner’s description.
Captain Tingirides was one of more than 50 officers assigned an armed security detail after the suspect’s online “manifesto” named those whom Dorner believed had wronged him. LAPD Chief Charlie Beck said: “Dorner did a lot of homework and that homework no doubt included some surveillance… it would perfectly fit in with what he was trying to accomplish.”