National Guard soldier deployed to South Texas to help secure border convicted of smuggling illegal aliens into US

CORPUS CHRISTI, Texas — A National Guard member deployed to South Texas to help secure the border was convicted of smuggling illegal aliens into the U.S. July 21. Findings of the smuggling were due to the combined investigation efforts of U.S. Immigration and Customs Enforcement Homeland Security Investigations Corpus Christi, the U.S. Department of Defense’s Office of the Inspector General Defense Criminal Investigative Service, and the U.S. Customs and Border Protection Office of Professional Responsibility.

Mario Sandoval, a 27-year-old resident of Houston, was found guilty of conspiring to smuggle illegal aliens at the end of a one-day trial in the U.S. District Court for the Southern District of Texas.

“Driven exclusively by greed, this individual betrayed the solemn oath he swore to defend when he enlisted in the National Guard,” said HSI Houston Special Agent in Charge Chad Plantz. “His actions directly undermined the very mission he was deployed to support and put his fellow guard members in danger. Working closely with our partners, we were able to expose his scheme and hold him accountable for this unconscionable betrayal of our nation’s trust.”

Sandoval was deployed to the U.S.-Mexico border with the Texas National Guard as part of Operation Lonestar. Following release from his orders, Sandoval remained in the Rio Grande Valley and began smuggling illegal aliens into the country in July 2024.

During his trial, the jury was provided with text messages from Sandoval’s phone expressing that drivers were needed for trips from the Rio Grande Valley to destinations north of the immigration checkpoint. Surveillance showed Sandoval’s location at the immigration checkpoint while he was sending text messages about law enforcement and K-9 patrol presence. The defense attempted to convince the jury no conspiracy existed, and his text messages were out of context. The Jury did not believe those claims and found Sandoval guilty as charged after deliberating for less than an hour.

“The conduct in this case represents an unthinkable violation of public trust,” said U.S. Attorney Nicholas J. Ganjei. “Thousands of brave men and women, military and civilian alike, work tirelessly to keep our border secure. It is truly disheartening that one bad apple chose to betray his fellow soldiers, his fellow citizens, and his country by engaging in human smuggling. I wish to thank the jury for their time and attention to this matter.”

Sandoval was discharged from the Texas National Guard in October 2024. He is scheduled to be sentenced Oct. 22. He faces up to 10 years in federal prison.

Assistant U.S. Attorneys John Lamont and Ashley Martin prosecuted the case.

For more news and information on how HSI Houston combats alien smuggling and other transnational criminal activity in Southeast Texas follow us on X at @HSIHouston.