First off, let me make it clear that it appears this dude is a complete scumbag and should have been fired.
I haven't seen what you are referring to, but it is plausible. When my ex and I were at our worst, that was one of the things she would do. She would hide my wallet, my work cell phone, anything that would force me to deal with her crap so that I could go to work. While I was looking for whatever was missing at the time, she would follow me around giving me grief, taunting me that i can't find it, yelling about whatever she had chose to fight about that day, or whatever. So if I changed directions or turned around, I was likely to run into her.
That being said, as a trooper he certainly was also aware that such happens frequently, and makes a good excuse.
Could have been some passive-aggressive crap like that, especially in a failing relationship.
But based on trooper’s past history of driving drunk in his patrol car, I figured he was drunk, and she didn’t want him on the road.