Under the Constitution, Police must have reasonable suspicion that there is criminal activity in progress before they can deploy a drug-sniffing dog. Now, in Colorado, recent case law has decided that an alert by a dog trained to detect marijuana is now considered a "search" in violation of the 4th Amendment of the US Constitution, for persons 21 years old and older.
"Because Amendment 64 legalized possession for personal use of one ounce or less of marijuana by persons twenty-one years of age or older in Colorado, it is no longer accurate to say, at least as a matter of state law, that an alert by a dog which can detect marijuana (but not specific amounts) can reveal only the presence of 'contraband.' A dog sniff could result in an alert with respect to something for which, under Colorado law, a person has a legitimate expectation of privacy, i.e., the possession of one ounce or less of marijuana for personal use...Because a dog sniff of a vehicle could infringe upon a legitimate expectation of privacy solely under state law, that dog sniff should now be considered a 'search' for purposes of article II section 7 of the state constitution where the occupants are twenty-one years or older. " People of the State of Colorado v. Kevin Keith McKnight, Colorado Court of Appeals No. 16CA0050 (July 13, 2017).
The reasonable suspicion standard requires “considerably less than proof of wrongdoing by a preponderance of the evidence and is less demanding even than the ‘fair probability’ standard for probable cause.” People v. Polander, 41 P.3d 698, 703 (Colo. 2001)
(quoting Alabama v. White, 496 U.S. 325, 330 (1990)). It is satisfied if “‘the police have specific and articulable facts, greater than a mere hunch, to support’ their belief
that the person to be stopped is or may have been involved in criminal activity.” People v. Huynh, 98 P.3d 907, 912 (Colo. App. 2004) (quoting Boylan, 854 P.2d at 812).
However, the Supreme Court expressly did not consider directly whether, given the recent changes to marijuana’s status in Colorado, an alert from a dog trained to detect marijuana and other controlled substances by itself establishes probable cause to search a vehicle.
I conclude that, for purposes of the Colorado Constitution, it does not.