Criminal investigators seeking suspects in difficult cases are asking Google to reveal who searched for specific information online, a practice known as reverse keyword warrants that Pennsylvania’s highest court upheld in late 2025 in a rape investigation. The technique identifies internet addresses where searches were made for particular terms—such as a street address where a crime occurred or phrases like “pipe bomb”—in a specific time window, then works backward to find suspects. While law enforcement has used the method to investigate bombings in Texas, the assassination of a Brazilian politician, and a fatal arson in Colorado, privacy advocates warn it turns innocent people into suspects by exposing their personal search histories.

The practice represents a collision between law enforcement’s need to solve crimes and constitutional protections against overly broad searches. As courts have upheld the warrants, civil liberties groups say the technique threatens privacy by giving police access to citizens’ deepest thoughts and concerns.

A Search Warrant That Names No Suspect

Pennsylvania State Police investigating a 2016 rape on a remote cul-de-sac outside Milton obtained a reverse keyword warrant directing Google to disclose accounts that searched for the victim’s name or address during the week of the attack. More than a year later, Google reported that two searches for the address were made a few hours before the assault from a specific IP address—a numeric designation indicating where a phone or computer connects to the internet. Police traced that address to John Edward Kurtz, a state prison guard.

After surveillance and DNA evidence from a discarded cigarette butt matched the victim, Kurtz confessed to the rape and to attacks on four other women over a five-year period. He was convicted in 2020 and is now 51. His sentence: 59 to 280 years in prison.

Kurtz’s attorneys argued police lacked probable cause to obtain the information and violated his privacy rights. The Pennsylvania Supreme Court rejected those claims in late 2025 but split on the reasoning. Three justices said Kurtz should not have expected his Google searches to be private. Three others said police had probable cause to look for anyone who searched the victim’s address before the attack. A dissenting justice said probable cause requires more than what defense attorney Douglas Taglieri conceded was “a good guess.”

How Reverse Keyword Warrants Work

Reverse keyword warrants differ from traditional search warrants, which target a known suspect or location. Instead, they work backward: investigators identify which internet addresses were used to search for specific information—such as a street address or phrases like “pipe bomb”—during a particular time window.

Prosecutor Julia Skinner, who handled the Pennsylvania case, said reverse keyword searches are most effective when they target specific and unusual terms: “I don’t think they’re used super frequently, because what you need to target has to be so specific.” In the Kurtz case, 57 searches were returned, though many came from first responders trying to locate the home immediately after the crime.

Similar Cases and Constitutional Questions

Police have used the method in multiple investigations. They sought anyone who searched for terms such as “low explosives” and “pipe bomb” while investigating a series of bombings in Austin, Texas. In Brazil, investigators trying to solve the 2018 assassination in Rio de Janeiro of politician Marielle Franco asked Google for accounts that searched for Franco’s name and the street where she lived. A Brazilian high court is expected to decide soon on the legality of those search disclosures.

A Colorado case illustrates the constitutional tension. Police sought anyone who searched for the address of a home where a deadly arson occurred. Authorities obtained IP addresses for 61 searches made by eight accounts, ultimately identifying three teenage suspects. Colorado’s Supreme Court ruled in 2023 that although the warrant was constitutionally defective for not specifying “individualized probable cause,” the evidence could be used because police had acted in good faith about what was known about the law at the time.

“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 ruled.

The Scope of Google Searches

For many people, Google search history contains deeply personal information: health concerns, political beliefs, financial decisions, spending patterns. The American Civil Liberties Union, the Internet Archive, and several library organizations warned in a brief filed in the Pennsylvania case that reverse keyword warrants give police “unfettered access to the thoughts, feelings, concerns and secrets of countless people.”

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

Google stated in response to questions about the warrants: “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.”

These warrants differ from “geofence” warrants, where investigators seek information about who was in a given area at a particular time. The U.S. Supreme Court said it will rule on geofence warrants’ constitutionality.

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