Abortion rights advocates are also concerned about geofence warrants, in which police ask Google to provide information on devices that were near the scene of a crime in order to find a suspect. That tool was found unconstitutional by a judge in Virginia last year, but that ruling doesn’t restrain police in other parts of the country.

Denver police, with help from the federal Bureau of Alcohol, Tobacco, Firearms and Explosives, turned to the keyword search several weeks after the fire, when they had yet to identify the people caught on security video in masks just before the fire was set.

The keyword search warrant, issued in November 2020, led Google to search for anyone who queried the address of the home that burned in the 15 days before the fire. Google delivered information on 61 queries, according to court filings, along with the IP address — a unique number for each computer on the internet. Investigators focused on a handful of those queries, asking Google to provide detailed user information for them. One of them was linked to the 17-year-old.

From there, investigators examined the teen’s other online activities, including Snapchat, Facebook, Instagram and text messages.  

The investigation revealed that the fire was set in a mistaken attempt at revenge against someone who’d stolen one of the co-defendant’s phones, a Denver detective testified last year. After the fire, the co-defendant realized the people killed were not the people he thought stole the phone, the detective said.

If it wasn’t for the keyword search warrant, investigators would never have suspected the 17-year-old or his friends, his lawyers wrote in the motion filed Thursday.

“The starting point was a search of billions of Google users, and all without a shred of evidence to search any one of them,” the lawyers wrote.

The lawyers called the search a privacy violation of not only the 17-year-old defendant but of all people who conducted a search on Google during the 15-day period.

The Denver Police Department declined to comment. So did the Denver district attorney’s office, which is prosecuting the case.

Price said that allowing the government to sift through Google’s vast trove of searches is akin to allowing the government access to users’ “thoughts, concerns, questions, fears.”

“Every one of those queries reveals something deeply private about a person, things they might not share with friends, family or clergy,” Price said. “‘Psychiatrists in Denver.’ ‘Abortion providers near me.’ ‘Does God exist.’ Every day, people pose those questions to Google seeking information.”