Sounds like a dick, but unless you actually saw him do it, then there's not alot you can do. Perhaps if you went to his house and asked him if he saw anything or anyone, and give him the chance to admit it, if he's a twat then i'd report him, not that they will do anything but it might be a deterrent in future.
Yeah hes a proper twat, we are silent, never make any noise etc, never even speak to him or acknowledge him, but yet he carrys on. I think the fact he doesnt work and stays at home all day doesnt help
He had a harassment order put on him by the previous neighbours about 6 years ago, and more recently he was told to "fuck off and get away from my house" from the guy about 6 houses down, every time he walked past his house he would stand by the gate watching the work men do work on his house and ask them questions and stop them from working, then the final straw was when he asked the workman if he got permission to install the gas tank he was having fitted.
Proper nosey twat, he needs to get his own life