In an interview with CTV News, a man the network identified as 22-year-old Daniel Ransem apologized to the school for the distress he caused.
Ransem, who is charged with malicious communications, told the network the post is ``a running joke'' on the 4chan forum and he had no malicious intent.
He says he has been released on bail and is due back in court in January.
The U.K.'s Malicious Communications Act makes it illegal for anyone to send a threat with the intent to cause distress or anxiety.
The post, which was initially flagged by U.S. authorities, triggered a lockdown of the Waterloo, Ont., campus for nearly six hours on Friday.