Colorado Supreme Court Undermines Fourth Amendment Protections in People v. Mills

On June 30, 2025, the Colorado Supreme Court handed down its decision in People v. Mills, No. 24SA148, reversing the Denver District Court’s suppression of drug evidence discovered after police held a suspect’s vehicle for three days before applying for a search warrant. While the Court’s majority couches its decision in a “reasonableness” framework, from a defense perspective, the ruling erodes the protections guaranteed by the Fourth Amendment.

What Happened in Mills?

Denver Police pulled over Arthur Mills on suspicion of narcotics activity. Rather than immediately searching his vehicle, the Denver Police Department (DPD) impounded it. Then, the DPD waited over 72 hours—three full days—before seeking a search warrant. During this time, Mills had no access to his vehicle, and the officers made no meaningful effort over the weekend to initiate a search warrant application.

The trial court ruled that the delay in seeking a warrant was unreasonable under the Constitution. However, on appeal, the Supreme Court reversed, adopting a new four-part balancing test that affords law enforcement greater leeway to delay searches after seizing personal property, even when probable cause is already present.

Why This Ruling Should Concern Us

From a civil liberties perspective, the Court’s ruling in Mills sets a troubling precedent. It opens the door for law enforcement to indefinitely hold property under the guise of “diligence” or “investigative complexity,” even where no meaningful action is taken for days. The constitutional standard is not whether a search warrant is eventually secured, but whether the delay in seeking that warrant is justified and minimally invasive. In this case, the lead narcotics detective, though off duty, made a conscious decision not to pursue a warrant over the weekend. He didn’t begin drafting the application until Monday and didn’t submit it until Tuesday, despite knowing the evidence had been in impound for the entire time. Under Mills, this passivity is now constitutionally sanctioned.

The New “Balancing Test”

The Court adopted a four-factor balancing test to assess whether warrant delays are reasonable: (1) length of delay, (2) possessory interest in the property, (3) government’s justification for delay, and (4) diligence in applying for the warrant. What this test gives in form, however, it takes away in substance. Instead of a bright-line rule limiting government intrusion, the Court now has a subjective standard that prioritizes government workload and officer discretion over an individual rights. In effect, police departments gain the ability to delay warrant applications for convenience, not necessity. By focusing on the fact that Detective Burke was “off duty,” the Court substitutes administrative expediency for constitutional compliance.

A Vehicle Today, a Home Tomorrow?

Though this case involved a vehicle, the legal principle stretches far beyond traffic stops. If police can now hold your car for 72 hours without a warrant simply because the lead detective had a day off, what’s stopping similar logic from being applied to electronic devices—or even homes? Should a driver on a DUI stop or traffic or lose their vehicle for days, or longer, due to police convenience. The Fourth Amendment exists to ensure that the state cannot detain or search property without timely judicial oversight. When that principle bends in the name of convenience, it ceases to protect.

Trial Court Got It Right

The trial judge in Denver applied a necessity-based test drawn from Chambers v. Maroney and other precedent: If the police seize property for the purpose of a warrant, they must act promptly to get one. That doesn’t mean officers must act perfectly or instantaneously, but it does require good-faith effort to minimize intrusion. In Mills, the delay wasn’t the result of complexity, unforeseen developments, or exigent circumstances, but a matter of priorities. The Court’s decision encourages that type of delay and hands prosecutors yet another tool to validate after-the-fact searches.

Conclusion

As a defense attorney, I respect law enforcement’s difficult role and recognize that investigations require time and care. But when we permit even minor erosions of Fourth Amendment protections, we chip away at the legal foundation that holds government power in check. The Mills decision isn’t just about a car or a delay. It’s about whether we allow our constitutional rights to be subject to administrative convenience. For those who value liberty and privacy, this ruling is a setback—and a call to remain vigilant.