The big question

Firstly, happy new year to all my readers. All two of you :D I am in a weird position at the moment. I will attempt to explain. Basically our next door neighbour rents his place from a sleazy guy who only cares about getting his money on time. The house is practicaly falling down. A couple of months ago the guy was arrested on a drug bust, and spent about 5 hours in prison before coming home again. Since then he has been keeping a really low profile. Really low. To the point that he doesnt even turn on his lights at night. Almost as if he is trying to make it look like he isnt there. But I digress. The other day we noticed that he has got his old car back. Some time ago his car died and he was without transport for a few days, then suddently a new car (new old car) appeared. Well now he has the old car back. But, the old car has the same tags as the new car did. So the question is this. Should I report this? And to whom? The thing is there is no way that he could have got the plates swapped legitimately because it happened on New Year's eve, after 6pm. So, do I call? Who do I call? Big question. I just nearly emailed autopac but then do I want my name associated with the tip? If you read this and have thoughts or suggestions (other than mind your own business) please let me know.

Thanks.