The person believed responsible for an attack targeting a Palm Springs fertility clinic Saturday posted rambling online writings before an explosion that investigators are treating as an act of terrorism, a law enforcement official told The Associated Press.

The blast, described as an intentional act of terrorism, shook the California city, blowing out windows of businesses.

An explosion outside a fertility clinic in Palm Springs, California on Saturday resulted in one fatality and four injuries, in what authorities are describing as an “intentional act of terrorism.” Pal