An Arizona state agency is throwing more doubt over the case of a sheriff's deputy who said he was shot by a band of illegal immigrants mere days after the governor signed the state's controversial immigration law, MyFoxPhoenix.com reported.

State Department of Public Safety investigators say what happened the night of the April 30 shooting was very unusual: The Pinal County sheriff's office initially called on them to do a full-blown investigation, but hours later, local authorities said they would take the lead instead.

Pinal County Deputy Louie Puroll said he was following a group of smugglers carrying bales of marijuana when he was ambushed by men firing AK-47 rifles. In what Puroll described as a running gunbattle, he was grazed by a bullet in the back.

The pathologists, Dr. Michael Baden of New York and Dr. Werner Spitz of suburban Detroit, examined photos of the wound released by the sheriff's office. They told The Associated Press on Friday that they concluded the bullet was fired from inches away, not from at least 25 yards away as Puroll said.

The sheriff's office soon after released a statement saying it stood behind the official investigation, and that physical evidence supports the deputy's account.

But the office reopened the case Monday, saying it wants to maintain transparency.

Pinal County Sheriff Paul Babeu told The Associated Press that the shirt Puroll was wearing the day of the shooting is being sent to the state Department of Public Safety for testing. The department will check for gunshot residue, charring, burning or any other evidence that it was a close-range shot.

"Clearly we don't have anything to hide," Babeu said. "If you think, 'Oh my God, this is the smoking gun,' we're going to send it to an outside agency and they're going to tell us."

Department of Public Safety Sgt. Kevin Wood said his department never had a major role in the investigation until now, which surprised him.

"I cannot remember a time when we have initially been asked to conduct a criminal investigation involving a shooting and then relegated to only doing the shooting scene or crime scene itself," Sgt. Wood told MyFoxPhoenix.com.

He said state investigators only helped collect evidence from the shooting scene -- they did not draw any conclusions.

Puroll's shooting fueled an already blazing debate in Arizona and the nation about the dangers of immigrant and drug smugglers in southern Arizona. It came just days after Gov. Jan Brewer signed a sweeping law giving law enforcers powers to question suspected illegal immigrants and arrest them. The major parts of that law have been put on hold by a federal judge on constitutional grounds.

The shooting immediately raised questions about a deputy supposedly looking for armed drug smugglers in the remote desert without backup. A dragnet involving more than 100 officers in the rugged mountainous area about 50 miles south of Phoenix found no suspects and no bales of marijuana.

The area is a well-known smuggling corridor for drugs and illegal immigrants headed from Mexico to Phoenix and the U.S. interior.

The Associated Press contributed to this report.