The shooter, Kori Ali Muhammad, is seen in an undated photo released by Fresno Police in Fresno, California, US, April 18, 2017. [Photo/Agencies]

Police confirmed that Muhammad is also suspected for the murder of a security guard outside Motel 6 in central Fresno on Thursday, but it was still too early to say if the shooting was an act of terrorism.

The shooting spree began around 10:45 am local time and 16 shots were fired at the four different locations in less than one minute.

Two of the people shot outside Catholic Charities may have been clients of the social service agency and the third victim was a passenger in a Pacific Gas & Electric truck. A fourth man was shot at but not injured, the Fresno Bee reported.