Yeah, I saw this story too. The customs guys seized his weapons, detained him, checked for warrants on him in both the US and asked the mounties if he had any in Canada. Having no basis to hold him, they kept his weapons and released him.

Then, after he was well on his way the mounties called back and said 'oh wait, that guy is a person of interest in a murder case'. Oops! So US authorities put out a BOLO for him and he was later picked up.