The stalking of Laura Black and subsequent murder of seven people and the injury of four by Richard Farley (February 16, 1988) and the three-year stalking and murder of actress Rebecca Schaeffer by Robert John Bardo (July 18, 1989) prompted California to pass the first anti-stalking laws in the country.
Although it wasn't brought up anywhere in the film, shortly before the ESL Incorporated Shootings, Farley had dated a woman, Mei Chang, while simultaneously stalking Laura. Chang claimed to be unaware of the extent to which Farley was harassing Laura or of his plans to kill people at ESL. Farley himself later testified (People V. Farley) that he never planned to kill anyone, and that his original plan had been to bring weapons to ESL and commit suicide in front of Laura to scare her, but he began killing people who he perceived as a "threat" upon reaching ESL's premises.
The scene in the film in which Farley bumps into Lawrence "Larry" Kane and remarks "cowboys and Indians!" before shooting him dead was not entirely accurate. The was never any evidence to suggest that Farley ever said anything to Kane before killing him, although supposedly Kane and most of the other employees of ESL did not get along with Farley. They thought he was eccentric and they were even afraid of him at times. Contrary to what the film portrays, Farley was large and overweight in stature, making him intimidating albeit not particularly violent at first. Farley and Kane were not close friends but they weren't enemies, either. It was assumed by investigators later on that Farley killed Kane simply because Kane surprised him by leaving the building when he wasn't expected to, or because Kane disapproved of the way in which Farley was treating Laura Black.
This film's fictional "Kensitron" was based on the real-life ESL Incorporated of Sunnyvale in which Richard Farley, an employee of Kensitron, became infatuated by a female co-worker, Laura Black, and this developed into an obsession and eventual mass murder resulting in California's introduction of its first anti-stalking laws, very progressive for the time (1989-90). As of 2018, Farley is still on Death Row in San Quentin, and continued to write letters from prison to Laura herself, telling her that she had "finally won" and maintaining the notion that they were destined to be together.
Initially Farley blamed Laura for the shootings, claiming that she led him on and flirted with him (even though from all accounts she did her best to avoid him entirely) and saying that he would not have killed anybody if she had just gone on a date with him. This attitude didn't do him any favors in court, and he was eventually sentenced to death in a California prison, although he is (as of 2018) still alive and remains on Death Row.