PHOENIX (AP) --
    Three weeks of growing fear among Phoenix drivers after a series of freeway shootings briefly eased when Arizona's governor blasted the news on social media: "We got him!"
    Republican Gov. Doug Ducey's tweet came just five minutes after a state police SWAT team arrested a 21-year-old father of two as he left a suburban Wal-Mart store Friday night.
    Ducey was almost immediately criticized for implying that Leslie Allen Merritt Jr. was guilty of the shootings before he had even been booked into jail or appeared in court.
    The message's celebratory tone also failed to convey a key fact about the arrest: Authorities have linked Merrill to only four of the 11 shootings, meaning other suspects could still be on the loose.
    "When he says, `We got him,' you don't `get' somebody until they're convicted or plead guilty," said Mike Black, a Phoenix criminal defense attorney for 30 years. "He's assuming this young man is guilty."
    Merritt is jailed as electronic freeway signs keep urging drivers to report tips. State police say copycats might be shooting guns or other weapons on freeways, so the investigation remains open.
    Within hours of Merritt's arrest, his father told The Associated Press that police got the wrong man and were scapegoating his son amid mounting public pressure to catch someone.
    In court the next morning, Merritt himself said he was innocent.
    "All I have to say is I'm the wrong guy. I tried telling the detectives that," Merritt said. "My gun's been in the pawn shop the last two months. I haven't even had access to a weapon."
    Court documents show police were looking for a specific brand and caliber of handgun after testing bullet fragments found in the first four vehicles hit by gunfire. They collected matching weapons from pawn shops, test-fired them and came up with a match to one Merritt had pawned.
    Department of Public Safety spokesman Bart Graves said Wednesday that the first shooting is now believed to have occurred on Aug. 27. Three other shootings on Aug. 29 had been thought to be the first in 11 incidents.
    The date change comes because the driver of a BMW that was hit was not sure when the shooting happened, Graves said. The car was parked at an airport Aug. 27 and retrieved Aug. 30.
    Graves said the change doesn't affect the charges against Merritt.
    Police spent Friday watching the landscaper's home, then trailed him to the Wal-Mart, and a SWAT team moved in.
    Five minutes later, at 6:52 p.m., Ducey took to Twitter: "BREAKING: We got him! DPS SWAT team is in custody of the individual suspected of I-10 shootings. Apprehended moments ago."
    Soon after, Ducey was accused of trying to win political points with an arrest that normally would be announced by the Department of Public Safety.
    Ducey spokesman Daniel Scarpinato said the governor thought it was important to inform the public of the arrest as soon as possible, and there was no political haymaking involved. Agency Director Frank Milstead had been briefing Ducey on developments regarding the suspect.
    "Here was an individual that had the entire community in panic, had injured someone, and the entire community was focused on looking for the individual who did this," Scarpinato said.
    Democratic Sen. Martin Quezada, whose Phoenix district straddles the parts of Interstate 10 where many of the shootings were reported, also said he was concerned the governor might be trying to gain political favor. But he said he understood Ducey wanting to quickly spread word of the arrest.
    "I can totally understand where the governor would want to put something out there, `We got the guy,'" Quezada said. "But on the other hand, you kind of sit back and reflect ... and you do realize the guy's only been arrested, and everybody deserves their day in court."
    Erik Luna, a criminal law professor at Arizona State University's Sandra Day O'Connor College of Law, said a defense attorney might consider the tweet substantial evidence that Merritt cannot get a fair trial. However, Luna believes the announcement was marginal because Ducey used the word "suspected."
    "I think that it raises valid concerns, and certainly it could be part of a broader claim of adverse publicity that results in a defendant not able receive a fair trial in a given jurisdiction," Luna said. "But by itself ... it seems a trial judge wouldn't grant such a motion based solely on that tweet."
    The arrest followed two false starts in the investigation.
    A week earlier, police took a 19-year-old into custody as a person of interest and later released him. Three young men also were arrested and accused of hurling rocks at cars with slingshots, but authorities called them copycats.
    Investigators say eight cars were hit with bullets and three were struck with projectiles such as BBs or pellets.