The story doesn't match up. Supposedly, he had a gun, then disarmed four policemen. So five guns total. Yet they found four guns on him. Why would he hide one gun, while keeping four? even if he was going full komrade, one gun on the belt and one on the ankle should have been the maximum.
My guess is he never had a fifth gun, meaning the cops were making shit up. Probably he managed to get one of their guns while still unarmed.
Which begs the question why he'd atack them in the first place - if he didn't carry a gun, he had nothing to hide. Combining this with the fact that the cops were illegally entering private property and illegally wanted to search them (both admitted to from the official side), I wouldn't be surprised if they'd have attempted to force him into complying, only for him to defend himself.
Not like it's a secret that german policemen are mostly corrupt bastards with little to no knowledge of the laws they're supposed to enforce.
I've even had a cop pull his gun on me for having a blunted sword (which I intended to buy) in hand at a fleamarket once, while claiming that it was allegedly an "Anscheinswaffe" ("pretendweapon") and illegal - even though the legal definition of "Anscheinswaffe" is a semi-auto or non-automatic gun looking like a full-auto gun, and they're only illegal to carry in public, but perfectly legal to own, while blunt swords are not even weapons by law, and legal to carry everywhere and by everybody. But hey, whatever feeds the sherrif's ego, I guess...