Someone caught cheating

[ericgtr]

On my site we have a guitar battle forum and we found one guy who has several different names registered under the same IP voting for himself. As far as I am concerned he's been caught red handed, however he is swearing up and down that it can't possibly be him. So I am going to throw this out there for you guys, I would like to get your opinions on it, in case I may be wrong or there is a chance this IP can be dynamically used by many.

The name he posts under mostly is rig96, here is what I get when I do an IP search for that username, all the IP's are the same:

dixielicks xx.xx.xxx.xxx [Find Posts by User] [View Other IP Addresses for this User]
kclad2000 xx.xx.xxx.xxx [Find Posts by User] [View Other IP Addresses for this User]
kotmjvip xx.xx.xxx.xxx [Find Posts by User] [View Other IP Addresses for this User]
pappalazaroo xx.xx.xxx.xxx [Find Posts by User] [View Other IP Addresses for this User]
rig96 xx.xx.xxx.xxx [Find Posts by User] [View Other IP Addresses for this User]
twatoth2005 xx.xx.xxx.xxx [Find Posts by User] [View Other IP Addresses for this User]

Registration IP Addresses
kc2000 xx.xx.xxx.xxx [Find Posts by User] [View Other IP Addresses for this User]
kclad2000 xx.xx.xxx.xxx [Find Posts by User] [View Other IP Addresses for this User]
mazolaboy xx.xx.xxx.xxx [Find Posts by User] [View Other IP Addresses for this User]
pappalazaroo xx.xx.xxx.xxx [Find Posts by User] [View Other IP Addresses for this User]
twatoth2005 xx.xx.xxx.xxx [Find Posts by User] [View Other IP Addresses for this User