(CNN) -- A U.S. Marine Corps reservist, who had hoped to be free after Wednesday's hearing in a Mexican court, was sent back to prison where he's been held the last three months on weapons charges.
Sgt. Andrew Tahmooressi's next day in court is August 4.
He's been imprisoned since March 31 when he drove into Mexico with three firearms in his truck.
Tahmooressi has maintained that he took a wrong turn on the California side of the border into Tijuana. He was detained by Mexican border officials for possessing a .45-caliber pistol, a 12-gauge pump shotgun and an AR-15 rifle.
Although he didn't gain his client's freedom, attorney Fernando Benitez said progress was made.
"It was finally and officially discovered that there are multiple irregularities with the order to search his vehicle," Benitez said.
The order was dated three days before the incident, according to Benitez, who said that at least 11 pages were missing from the record presented in court.
He also contends the Marine reservist wasn't given adequate access to translators.
The director of the Tijuana checkpoint told Mexican media last month that Mexican agents at the border gave Tahmooressi a chance to surrender his weapons and return to the United States without incident. Tahmooressi told CNN that's "a lie."
"That's not true at all. They never told me anything of that sort," he said in jailhouse interview on Sunday.
Tahmooressi said the Spanish translator provided to him at the border added to the confusion in communication.
"After I had got off the phone with 911 and I felt like there was no one there to help me, I even told them, I said, 'You can take my guns, take my truck and take all my possessions, just let me go back to America.' And they shook their head no in frustration."
Asked by CNN if he believes he should receive punishment for his mistake, Tahmooressi said no.
"I feel like the punishment was never necessary from the beginning. But once the (Mexican) military people got involved, they were like, 'Look what we found, we found these guns, good for us. Let's get this guy incriminated.' There was some good people at the border who were going to do the right thing, and that's how it should have been from the start."
Following Wednesday's hearing, Jill Tahmooressi meet with her son for 20 minutes. They both remain hopeful.
"He is strong, he is confident and he is very privileged to have Mr. Benitez defend his innocence," she said.
CNN's Nick Parker contributed to this report