Texas Ranger Sgt. David Armstrong is facing criticism for supporting Amber Guyger, the Dallas police officer who shot and killed an unarmed black man in his own apartment last year.

Speaking at Guyger's trial Wednesday, Armstrong said Guyger didn't commit a crime when she shot Botham Jean and that she had reason to believe she was entering her own apartment.

Armstrong said it was a reasonable perception for Guyger to believe there was a burglar in her apartment.

Armstrong said Guyger didn't have time to formulate a plan or call for backup because the incident wasn't like a typical response to a burglary call.

"It was a reasonable perception," Armstrong said. "I believe she did perceive him as a deadly threat."

Armstrong added that the shooting "wasn't reckless or criminally negligent based on the totality of the investigation and the circumstances and facts.”

According to CNN, Guyger's attorney said she was tired after work and on "autopilot" when she missed signs that could have shown her she was heading to the wrong apartment. 

The attorney said Guyger wasn't paying attention when she parked in the garage, where the numbers aren't clearly marked on the floor.

Many expressed their frustration on social media after Armstrong's comments.