AUSTIN (KXAN) — After the Austin American-Statesman posted leaked video of the moments inside Robb Elementary school where two teachers and 19 students were shot and killed, a legal expert tells KXAN it’s possible the Uvalde County District Attorney or state officials could pursue a criminal investigation into the law enforcement response.

The full 77-minute video shows the gunman enter the school through an unlocked door, step into a classroom and start firing with his semi-automatic rifle. Three minutes later, police can be seen in the video moving from two ends of the hall to approach the classrooms where the gunman was.

The officers appear to take fire before retreating back to the end of the hall where they would remain for more than an hour. There are several agencies represented in the video and all have received sharp criticism from the community, lawmakers and law enforcement experts. But the question remains, will they face charges?

That legal process has already proven to be difficult, perhaps most notably on display in the case against a former school resource officer in Parkland, Florida. That officer is awaiting trial on charges of child neglect under a state “caregiver” law. He is accused of failing to act during the mass shooting at a high school that left 17 people dead four years ago.

But, a criminal defense attorney and former prosecutor in Travis County told us those kinds of cases are rare because the burden of proof in criminal court is so high.

“The burden of proof in civil cases is much lower than it is in criminal court, so it is much easier to prove their case,” Jeremy Sylestine said. “In this situation, there very well could be a grievance that a family, a member of the community wants to exercise in the civil courts.”

Sylestine does not believe there would be a criminal investigation in the leak of the video itself, but that it could spark a policy change or internal investigation within the department that released the video to Austin media outlet.