The first police officer to respond to a Milverton home after a double shooting testified Thursday at the trial of the man accused of pulling the trigger.

Const. Christian St-Amour told the court that he arrived at the house shared by Michael Schweitzer and Tyler Baker around 10:25 p.m. on Dec, 4, 2012 – about five minutes after Baker called 911.

St-Amour said that he arrived with information that at least two people were hurt, and the weapon that injured them was in the area.

When he got to the Edward Street property, he said, there were three people outside – including Schweitzer and his father Murray.

Murray Schweitzer was handcuffed and placed in the back of St-Amour’s cruiser for “his safety,” the officer said.

Once other officers arrived, Michael Schweitzer was placed in the back of the same cruiser.

As the other officers went inside to search the home, St-Amour remained outside, near his cruiser.

Jurors heard that St-Amour could hear what Michael Schweitzer was saying inside the cruiser, as one of the windows was lowered.

St-Amour testified that he heard Schweitzer repeatedly ask if Baker was OK, and repeatedly say “I can’t believe what I’ve done” as he knocked his head against the Plexiglas divider in the cruiser.

He continued to repeat the same two comments as St-Amour took him to the OPP detachment in Sebringville, St-Amour testified.

Seventeen-year-old Nicole Wagler was found dead inside the home.

Baker was critically injured. While he survived, he still has facial scars from the injuries he received.

Schweitzer was arrested less than an hour after police arrived at the scene.

He was subsequently charged with first-degree murder and attempted murder, and has pleaded not guilty to both offences.

St-Amour’s testimony continues Friday.