Let's look at the timeline - enough time elapses for one guy to go upstairs complaining, and the carpenter to go back down there and find him - with 'matters still in hand', so to speak.
Unless he has a serious prostate problem - he ought to have been done with business by then, one would think.
I'd guess that things are as they appear - a perv hanging around the bathroom looking for thrills. Besides, the cops did arrest the guy - I would hope that they did little investigation and assessment to ensure that they weren't compounding a miscarriage of justice.
You're probably right but I'd still like to see a little more corroboration.