Throwing someone out is not a criminal matter what the soldier in question should do is file eviction proceedings in civil court against the occupant and eventually the judge will issue a writ of possession which the sheriff will execute. The problem is that if the sheriff threw anyone and everyone out on someone’s say so then a lot of people that pissed off their landlord would be tossed out on the street. This way there is an orderly process to follow and the judge makes the call on tossing them out.
I think you’re right - there’s a process to be followed for this sort of thing. Chances are (unless there’s a lot more to this story than we’ve heard so far, which is certainly possible) that it should be pretty much a formality to get an eviction order. I doubt if the current occupants have much in the way of resources to fight it in court.
In a perfect world scumbags like these (if that’s what they are - again we may not have heard to whole story) would also be charged with fraud, or theft, or something like that. A person could probably take them to civil court for damages, but you can’t squeezed blood from a stone.