"We got him! DPS SWAT team is in custody of the individual suspected of I-10 shootings. Apprehended moments ago," Arizona Governor Doug Ducey said on Twitter.
At a late Friday news conference, law enforcement officials gave few details of the suspect and did not release his name, but said a gun he owned was "forensically linked" to the first four shootings on the highway.
Authorities have been investigating about a dozen possible vehicle shootings since Aug. 29 on a roughly 10-mile (16-km) stretch of Interstate 10 through Phoenix. A 13-year-old girl who suffered a slight cut to her ear has been the only injury reported.
State and federal law enforcement were confident the suspect in custody was involved in at least the first four shootings, said Colonel Frank Milstead, director of the Arizona Department of Public Safety.
He did but did not rule out the possibility of copycats in other incidents along the roadway.
"Are there copycats? That's possible," Milstead said.
The male suspect was taken into custody on Friday after being watched by law enforcement, officials said.
"We've had our eyes on him for a while," said Arizona Department of Public Safety spokesman Bart Graves.
ABC affiliate KNXV-TV, citing multiple sources, said the suspect was found trying to pawn the gun used in the shootings.
The shootings have caused anxiety for motorists using the stretch of I-10, the southernmost transcontinental highway in the United States, which runs through the Phoenix metro area.