The suspect believed to be responsible for detonating a car bomb outside of a California fertility clinic has been identified.

Guy Edward Bartkus, 25, is accused of setting off the blast just before 11am Saturday at the American Reproductive Centers in Palm Springs inside a silver Ford Fusion sedan, the FBI said.

Bartkus is the only person who died in the incident, which authorities are calling an 'intentional act of terrorism.'

Four others were injured from the blast but none of them are employees of the clinic, according to city officials.

In his writings, Bartkus allegedly said he was 'pro-mortalist', something he described as someone who intends to bring on their own death as soon as possible 'to prevent your future suffering, and, more importantly, the suffering your existence will cause to all the other sentient beings.'