SURPRISE, Ariz. — One person was killed and 12 others injured in reported drive-by shootings over a 90-minute span Thursday in three cities west of Phoenix, authorities said.

A suspect was in custody, and authorities said a weapon was found in his vehicle. But it remained unclear if the man was responsible for all of the shootings.

The suspect’s name wasn’t immediately released. Authorities believe he acted alone, although a motive wasn’t immediately known.

“We don’t know the nexus, we don’t know what the motive was, we don’t have an idea of what this person was thinking when he went out and did this,” Peoria police spokesman Brandon Sheffert said at a news conference. “Obviously we want to figure this out because there’s a lot of scared people and people this affected.”

Police departments in Peoria, Surprise and Glendale were investigating the shootings in their cities, along with the Arizona Department of Public Safety and the FBI.

Authorities were combing through at least eight separate shooting scenes, Sheffert said.

Four people suffered gunshot wounds, and one of those victims died, he said. That person was found dead in a vehicle along a Peoria freeway.

The other victims had a range of injuries such as shrapnel from broken glass or injuries related to a car crash, Sheffert said.

Officials at Banner Health said they received nine patients at three of their hospitals. But the extent of the victims’ injuries and their conditions were not immediately released.

Peoria police got the initial call about a shooting shortly after 11 a.m., and eight more incidents were reported in the following 90 minutes, Sheffert said.

Witnesses provided authorities with a description of the getaway vehicle, and the suspect was detained after a traffic stop in Surprise.