A SWAT team have stormed a Wal-Mart store in Arizona and arrested a man in connection with a spate of highway shootings in Phoenix.
But officials said copycats might still be at large and the investigation was continuing.
Leslie Allen Merritt Jr was linked to at least four of 11 seemingly random shootings that took place between 29 and 30 August.
He faces charges including criminal endangerment, assault and unlawful discharge of a firearm.
The 21-year-old was arrested as he was trying to allegedly pawn the gun used in the shootings, officials said.
Officers armed with semiautomatic weapons stormed the crowded Wal-Mart in Glendale, a suburb west of Phoenix, and came out with suspect in handcuffs.
A woman and five-year-old child who were with him were not taken into custody, CBS reported.
"We got him!" Governor Doug Ducey tweeted. "Great work by Arizona DPS [Department of Public Safety] investigators and SWAT team."
There have been no serious injuries as a result of the shootings, but one teenage girl needed treatment after a bullet shattered the windscreen of a car she was travelling in, cutting her ear.
Police say Merritt shot at a tour bus, SUV and two cars, all of them on the Interstate 10, a major route through the city.
It was not clear who might be responsible for the other shootings.
"Are there others out there? Are there copycats? That is possible," Department of Public Safety Director Frank Milstead said.
The suspect's family came to his defence. His father said Merritt was being made a scapegoat by police who had come under public pressure and was keen to make an arrest.
"He has way too much value for human life to even take the slightest or remotest risk of actually injuring someone," Leslie Merritt Sr told the AP news agency.
The suspect’s Facebook page suggested he was a gun enthusiast.
Prior to the suspect's arrest, the head of the state police had described the incidents as "domestic terrorism".
A reward of $50,000 (around €44,000) was being offered for any information which could have led to an arrest and conviction in the case.
Meanwhile, a 19-year-old detained outside a convenience store on 11 September in connection with the shootings has been freed – with investigators saying he was not a prime suspect.
In 2005 and 2006, Phoenix was terrorised by another spate of serial shootings.
Eight of the 29 people shot were killed, including a cyclist riding down the street, and a man sleeping at a bus stop.
Dale Hausner was sentenced to death following the shootings – but in June 2013, he died after being found unresponsive in his cell because of an anti-depressant overdose.
His former roommate, Samuel Dieteman, is serving a life sentence without parole.
