"They still use marijuana to train the dogs," said Steve Davis, a Lakewood police spokesman. "If a dog hits on marijuana, you don't know whether you're going to find one ounce in that suitcase or six pounds."
The conflicting views at police departments in Colorado and Washington over whether the legalization of cannabis requires a new way of thinking about how they train their K-9 units may ultimately be resolved by judges.
"The federal courts said a dog's nose is special, it doesn't fall under the regulation of the Fourth Amendment," which prohibits unlawful search and seizure, said Mary Fan, who teaches law at the University of Washington in Seattle.
"In Washington we have a more protective constitution and we said even if that's so under federal law, we think it's intrusive to have a dog walk up and sniff our stuff," she said. "This just adds yet more layers of complexity to the already existing debate as to how much we want to regulate the use of sniffer dogs."