Courts Debate Privacy as Police Use Google Searches to Catch Criminals

Law enforcement agencies are increasingly using "reverse keyword" warrants to identify suspects by requesting Google reveal who searched for specific crime-related terms. Privacy advocates warn this practice threatens innocent people's rights while courts remain split on its constitutionality.

HARRISBURG, Pa. — Law enforcement agencies investigating challenging criminal cases are turning to Google with requests to identify users who conducted specific online searches, using what are called “reverse keyword” warrants that civil liberties advocates say put innocent citizens’ privacy at risk.

These warrants operate differently from standard search warrants that focus on known suspects or specific locations. Instead, keyword warrants work in reverse by pinpointing internet addresses where particular search terms were entered during specific time periods, including street addresses of crime scenes or phrases such as “pipe bomb.”

Investigators have employed this technique while working cases involving Texas bombing incidents, the murder of a Brazilian political figure, and a deadly arson case in Colorado.

Law enforcement’s interest in Google search data makes sense given the search engine’s role as the primary internet gateway and the extensive digital footprints people leave behind daily. This data proves especially valuable when investigators have no suspects, such as in the search for Nancy Guthrie’s abductor.

The constitutional battle between solving crimes efficiently and Fourth Amendment protections against excessive searches recently came before the Pennsylvania Supreme Court, which approved using a reverse keyword warrant in a sexual assault case.

Civil liberties organizations view this practice as providing law enforcement “unfettered access to the thoughts, feelings, concerns and secrets of countless people,” stated an amicus brief submitted during the Pennsylvania case by the American Civil Liberties Union, the Internet Archive, and multiple library groups.

When asked about these warrants, Google responded via email: “Our processes for handling law enforcement requests are designed to protect users’ privacy while meeting our legal obligations. We review all legal demands for legal validity, and we push back against those that are overbroad or improper, including objecting to some entirely.”

Pennsylvania State Police faced a dead end while investigating a brutal sexual assault that occurred in 2016 on an isolated cul-de-sac near Milton, a small central Pennsylvania town. Without viable leads, investigators secured a warrant requiring Google to reveal accounts that had searched for the victim’s name or home address during the week of the attack.

Over a year passed before Google disclosed that two searches for the woman’s address had been conducted hours before the assault from one particular IP address, which identifies a device’s internet location.

This information directed investigators to the residence of state prison guard John Edward Kurtz.

Authorities then monitored Kurtz and retrieved a discarded cigarette that provided DNA evidence matching samples from the victim, court documents show. He admitted to the rape and additional attacks on four other women spanning five years, receiving a conviction in 2020. At age 51, he was sentenced to 59 to 280 years in prison.

Kurtz’s defense team contended that police lacked sufficient probable cause for obtaining the information and violated his privacy rights.

The state Supreme Court dismissed these arguments last year, though justices were divided in their reasoning. Three justices concluded Kurtz had no reasonable expectation of privacy regarding his Google searches, while three others determined police had probable cause to investigate anyone who searched the victim’s address before the attack. However, one dissenting justice argued probable cause demands more than a “bald hunch” and speculation that a criminal might have used Google.

Defense attorney Douglas Taglieri echoed this concern in court documents but acknowledged, “It was a good guess.”

Prosecutor Julia Skinner, who handled the case, explained that reverse keyword searches work best with specific or uncommon terms that limit results, such as unique names or addresses. They’re also most effective for crimes that appear premeditated, she noted.

“I don’t think they’re used super frequently, because what you need to target has to be so specific,” Skinner said. The Kurtz investigation returned 57 searches, though many came from first responders attempting to locate the residence immediately after the crime occurred.

In the Colorado arson case, police requested IP addresses for anyone who searched a home’s address over 15 days where a fatal fire took place. Authorities received IP addresses for 61 searches from eight accounts, ultimately helping identify three teenage suspects.

The Colorado Supreme Court determined in 2023 that while the keyword warrant was constitutionally flawed for lacking “individualized probable cause,” the evidence remained admissible because police acted in good faith based on existing legal understanding.

“If dystopian problems emerge, as some fear, the courts stand ready to hear argument regarding how we should rein in law enforcement’s use of rapidly advancing technology,” the Colorado justices’ majority ruled.

Courts have historically allowed investigators to obtain materials like banking records or telephone logs. However, civil rights organizations argue that extending these powers to online keyword searches makes every internet user a potential suspect.

The annual number of keyword warrants remains unknown — Google doesn’t categorize the warrants it receives by type, according to a January 2024 brief from the Electronic Frontier Foundation and the Pennsylvania Association of Criminal Defense Lawyers.

These organizations reported that police investigating the Austin, Texas bombings sought individuals who searched terms including “low explosives” and “pipe bomb.” In Brazil, investigators working the 2018 assassination of Rio de Janeiro politician Marielle Franco requested information about those who searched Franco’s name and her street address. A Brazilian high court is expected to rule soon on those search disclosures’ legality.

Reverse keyword warrants differ from “geofence” warrants, where investigators seek data about individuals present in specific areas at particular times. The U.S. Supreme Court announced last month it will decide on that method’s constitutionality.

For many users, their Google search history reveals highly personal information, including health concerns, political views, financial choices, and spending habits. Google’s integration of more artificial intelligence into its search platform appears designed to gather even more user data.

“What could be more embarrassing,” questioned University of Pennsylvania law professor and civil rights attorney David Rudovsky, if every Google search “was now out there, gone viral?”

Google informs users that personal information may be shared externally when the company has a “good-faith belief that disclosure of the information is reasonably necessary” to comply with applicable laws, regulations, legal processes, or an “enforceable government request.”

In the Kurtz case, Pennsylvania Justice David Wecht distinguished between Kurtz’s decision to search for the victim’s name on Google and a 2018 U.S. Supreme Court ruling that restricted broad cellphone location data collection.

“A user who wants to keep such material private has options,” Wecht wrote. “That user does not have to click on Google.”