Here is a copy of an email I just received from AVS:

"beatboy77,

Your account on AVS Forum has been locked because someone has tried to
log into the account with the wrong password more than 5 times. You
will be able to attempt to log in again in another 15 minutes.

The person trying to log into your account had the following IP
address: **.***.***.***

Don't forget that the password is case sensitive. Forgotten your
password? Use the link below:
http://www.avsforum.com/avs-vb/login.php?do=lostpw

All the best,
AVS Forum team"

How can I find out who this is and report them?

~Josh

The system did give you the IP address, that is really all you would have to go on. Thought it is not much.

I saw the IP address before it was removed. Whoever it was used a proxy. Goodluck with that one.