( 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 did n'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 . Mother : My son is detained in Mexico . 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 was n'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 .
Andrew Tahmooressi will be back in court August 4 . Tahmooressi was arrested in March for crossing into Mexico with three firearms . He says he took a wrong turn and would never consider trafficking in guns .