Three people were killed in "random" and "unprovoked" shootings that unfolded in a matter of seconds in Fresno, California, authorities said.
Police said they quickly arrested a suspect who they determined has previously expressed anger towards white people and the government. When the suspect was taken into custody, he yelled "Allahu akbar," according to Jerry Dyer, the Fresno police chief.
Authorities identified the suspect as 39-year-old Kori Ali Muhammad and described him as a man with a lengthy criminal history who went out intending to kill people. Police said he dived onto the ground when he saw an officer before being taken into custody.
"This was a random act of violence," Dyer said at a briefing. "These individuals that were chosen today did not do anything to deserve what they got. These were unprovoked attacks by an individual who was intent on carrying out homicides today, and he did that."
Dyer said police have examined Muhammad's Facebook account, where they found "some posts that say he does not like white people" as well as others that "expressed some antigovernment sentiments."
Based on the Facebook postings and Muhammad's exclamation today, police contacted the FBI about the shootings, Dyer said.
"I'm certain they're going to be very interested in this case," he said.
Dyer said police believe Muhammad acted alone. The police chief said it was too soon to say whether the incident involved terrorism, but he added, "Certainly, by the statement that was made, it would give that indication."
However, Dyer also said that the suspect is also believed to have fatally shot a security guard at a motel in the city last week and that he did not make any comments or statements at that time.
Dyer said it is "not certain why he said what he said today" but vowed that investigators were "trying to determine why he did what he did".
The three people killed today were white men, as was the motel security guard, Dyer said.
If investigators determine that the suspect was inspired by international terrorist groups, it is likely that the FBI would take over the case, but so far, local detectives are handling the probe with assistance from federal agents, according to law enforcement officials.
Police had identified Muhammad, who also goes by the nickname "Black Jesus," last week after the motel shooting based on video from the scene, Dyer said. After shooting the unarmed security guard at the motel last week multiple times, the police chief said, Muhammad also fired at another guard.
Authorities did not publicise his identity as they were chasing possible sightings of Muhammad and other leads in the case, Dyer said. According to the police chief, Muhammad has had some associations with gangs but is not believed to be a gang member.
The Fresno County Sheriff's Office said Muhammad is a homeless man known to frequent areas near the Fresno City College and other parts of the city. The imam of the Islamic Cultural Centre of Fresno told AP that Muhammad is not a member of the centre.
Police described the people killed today, who were not immediately identified, as simply being in the wrong place at the wrong time.
One man shot was the passenger in an electric company's truck. Another man was shot while encountering the shooter on the street, police said, while the third victim was in a parking lot. Dyer also said that the shooter fired several rounds at another person in the area but missed each time.