A former McAllen Police Department officer was one of the three officers shot Saturday in San Marcos, Texas.

Franco Casey Stewart served in the Texas National Guard from September 2014 to January 2015 and was deployed to the U.S.-Mexico border as part of Operation Strong Safety.

Stewart joined the McAllen Police Department in June of 2015 and resigned in May of 2018 to join the U.S. Border Patrol, according to his resignation letter.

According to the Associated Press, the officers responded to a 9-1-1 call about a man in the apartment who had hit his wife and was threatening other family members who were there.

When officers went inside the building the “suspect fired on them with a rifle as soon as they entered,” according to the Associated Press. The attacker was later found dead of an apparent gunshot wound.

The attack left Officer Justin Putnam, 31, dead - Stewart and Officer Justin Mueller remain in critical condition.