The FBI is investigating the explosion at a California fertility clinic as an act of terrorism

The person believed responsible for an attack targeting a Southern California fertility clinic Saturday posted rambling online writings before an explosion that investigators are treating as an act of terrorism, according to a law enforcement official.

The suspect, who died in the explosion that tore through the clinic and rattled the upscale California city of Palm Springs, also attempted to record video or stream the attack, said the official, who was not authorized to discuss details...