I talked with one of the investigators today. The rifle was a Browning. Function testing hasn’t been competed yet.
I had a Browning A-bolt that fired when the bolt was closed with nothing anywhere near the trigger. Was hunting cold, deer came in, chambered a round and it fired as soon as the bolt closed. Sent the gun into Browning and they found the defect and repaired it. So, I know personally that it can happen with a Browning. Don't know if his was same model. Scared the [bleep] out of me when it went off.
He still violated rule #1.