DALLAS (CBSDFW.COM) – Jurors in the trial of former Balch Springs police officer accused of murder, heard a law enforcement specialist Tuesday strongly criticize Roy Oliver’s decision to open fire on a vehicle killing a teenager.

Former Balch Springs Police officer Roy Oliver faces one count of murder and two counts of aggravated assault by a peace officer.

Roy Oliver on trial (CBS11)

In April of 2017, Oliver shot and killed Mesquite High School student Jordan Edwards.

Edwards was riding in a car driven by his brother. They were leaving a house party. Police responding to a 911 call heard shots fired near the party.

Oliver and officer Tyler Gross tried to stop a car driving from the party area. Oliver fired five shots from his semi-automatic rifle, killing Edwards with one of the shots.

Philip Hayden is a noted expert in officer training for use of force scenario. Testifying Tuesday, Hayden told the jury, Oliver and Gross were properly responding to the disturbance. But Hayden explained Oliver’s decision to fire at the car as excessive and unreasonable.

He also rejected Oliver’s claim that he used deadly force because the driver of the car was moving toward Officer Gross.

“I did not see any reason why Officer Oliver felt like he had a necessity to fire his weapon at all. I believe there’s enough data here to say what happened is Officer Oliver did not have a reasonable belief to use deadly force, and he should not have used deadly force,” Hayden told jurors.

Previous testimony before jurors from Officer Gross included his statement that he felt no threat from the car Edwards and the other boys were riding.

The trial continues Wednesday.