OMAHA, Neb. (AP) — Jurors at the trial of a former Omaha police officer charged with assault stemming from a deadly encounter with a mentally ill man will not learn that it led to the officer’s firing, a judge ruled.

Scotty Payne, 39, is charged with felony assault and use of a weapon in the June 5, 2017, death of Zachary Bearheels. Police said Bearheels, 29, was acting erratically at an Omaha convenience store and fought officers’ efforts to take him into custody. He lived in Murdo, South Dakota.

At a pre-trial hearing Thursday, Judge J. Russell Derr ruled that jurors won’t hear that Payne was fired for violating procedures, including the barred use of a stun gun on a handcuffed person. Derr also barred testimony about why Payne’s police body camera wasn’t turned on and why he rode in the ambulance with Bearheels, the Omaha World-Herald reported.

Police cruiser video shows Payne using the stun gun on Bearheels and Officer Ryan McClarty dragging Bearheels by his hair and repeatedly punching him in the face. McClarty is due to stand trial in January on a misdemeanor assault charge.

Douglas County Attorney Don Kleine said he decided against more serious charges because a coroner could not directly link the officers’ actions to Bearheels’ death. The coroner determined that Bearheels’ cause of death was excited delirium and other factors, including the stun gun jolts. Medical experts say excited delirium is characterized by agitation, aggression, acute distress and sudden death.

The judge barred the two sides from mentioning any possible link between the stun gun shocks and excited delirium, but the coroner will be able to testify about other issues, including whether Bearheels suffered pain from Payne’s actions.

The trial is scheduled to begin Nov. 26.