The mother of a North Carolina Central University student fatally shot by a security guard is demanding answers, saying the details surrounding her son’s death just don’t add up.

The Durham Police Department said it’s investigating after DeAndre Marquise Ballard, 23, was shot and killed at an off-campus housing complex on Sept. 17. As reported by The Herald Sun, police responded to a call of a gunshot wound at the Campus Crossings apartments around 10:30 p.m.

There they found Ballard, who was rushed to a hospital, where he later died. A security guard hired by the university fired the fatal shot.

“The case remains under investigation,” police spokeswoman Kammie Michael said. “No charges have been filed at this time.”

Authorities said N.C. Detective Agency, the security firm hired to patrol the complex, insisted the guard acted in self-defense in shooting Ballard, a graduating senior at the Durham university. The firm said Ballard was reportedly breaking into students’ cars and got into a scuffle with the security guard.

“We fully, 100 percent stand by his actions because this was self-defense,” said Kevin Ladd, Vice President of the N.C. Detective Agency. “In our eyes this is a tragic accident. It never should have gotten to this, but our officer was fearful for his life.”

Ballard’s mother, Ernisha Ballard, says the story is hard to believe, however, seeing as her son was “terrified” of guns. Moreover, she said they’d had talks about staying safe when dealing with law enforcement.

In an interview with WRAL, the elder Ballard said police told her the security guard saw her son breaking into cars at the complex. He then got into the security guard’s car, entering in on the passenger’s side. That’s when a fight ensued, she was told, and Ballard grabbed for the guard’s gun, causing it to go off. He was shot around 10:15 p.m.

“According to the security guard, he was saying that he was trying to fight him, trying to get his gun,” Ernisha Ballard told the station. “I just find that hard to believe, that DeAndre would do anything like that.”

“There’s no way. I don’t even buy that,” she added.

DeAndre Ballard’s close friend, Brian Best, said he doesn’t believe the guard’s story either.

“Durham needs to do a very thorough job of investigating this and getting to the truth,” Best said. “What we have now is definitely not that.”

Earlier this week, the N.C. Detective Agency said the guard, who remains unnamed, is state certified and has 15 years experience. He was placed on administrative leave for a week after the shooting but returned to work at a different site Monday, The Herald Sun reported.

Ladd described the guard as African-American.

“We have never had anything like this,” Ladd said. “We feel terrible about it. Our officer feels terrible.”

Agency director Brian Jones said he’s monitoring the situation and will decide whether to launch its own investigation after Durham police finishes theirs.