EL PASO, Texas (KTSM) -- An 18-year-old man was arrested last week at Andress High School in El Paso and is facing charges, including aggravated assault with a deadly weapon, after he was found to have a gun on campus, according to court documents obtained by KTSM. Xavier Gasca, 18, was arrested Friday afternoon, Sept. 27 after El Paso Independent School District Police were tipped off that he had a gun on campus. He is facing a charge of aggravated assault with a deadly weapon after he allegedly assaulted his girlfriend earlier. Gasca is also facing a charge of having a prohibited weapon on campus, possession of a controlled substance and possession of less than 2 ounces of marijuana. At about 1 p.m. on Friday, EPISD Police arrested Gasca in an auditorium that was full of students for a fine arts presentation. A concerned parent notified police that his daughter -- the suspect's girlfriend -- had gotten into an argument with him and the parent told district police that Gasca had a weapon, according to court docments. The school was placed on a "lockout secure hold" and Gasca was found in the fine arts building in an auditorium full of students, according to court documents. Police called out the suspect's name several times in the auditorium and the suspect raised his hand to identify himself. He was taken into custody along with a backpack that he was carrying, the court documents said. Inside the backpack, police found a handgun with an extended magazine loaded with 25 rounds of 9mm ammunition, according to court documents. Police also found that Gasca had two vape pens in his possesion and two bags that were described as having a "green leafy substance." During the investigation, police talked to the suspect's girlfriend. Police saw that she had several visible injuries like a purple bruise on her arm and a red scratch on her chest and lower abdomen. The girl told police that the suspect had caused those marks and injuries by physically hitting her. The girl also told police that they had been dating as boyfriend and girlfriend for about eight months. The girl said that the abuse started back in April and the last incident of physical abuse had happened on Sept. 23, just a few days before Gasca's arrest on campus, according to court documents. The girl told police that the suspect drove her to the desert where he pulled a gun on the victim and told her he was going to kill her and himself, according to court documents. At that point, the suspect put the gun away, according to court documents. The victim told police that the suspect hit her in the face and head, twisted her arm and suffocated her by choking her until she lost consciousness. He also threw his backpack at her, striking her in the head, according to court documents. Police said the injuries that they observed were consistent with the victim's statement.