Law Enforcement Agencies Can’t Share Data Under 4th Amendment

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By Tera Brostoff

A federal agency needed a second search warrant to review data obtained in a state investigation of unrelated charges, the U.S. District Court for the District of South Dakota held Feb. 17 ( United States v. Hulscher , 2017 BL 49646, D.S.D., No. 4:16-CR-40070-01-KES, 2/17/17 ).

Judge Karen E. Schreier’s decision suggests that law enforcement agencies should think twice before sharing data in the spirit of “collaboration.”

The decision also highlights the increasingly common belief that data is different, following the Supreme Court’s decision in Riley v. California, 134 S. Ct. 2473 (2014). Because electronic data can provide so much information about an individual, courts have placed restrictions on getting and sharing data that go beyond what may be required for other types of evidence.

The Huron Police Department investigated Robert Hulscher on forgery and counterfeiting charges. During its investigation, the police department got a warrant to search Hulscher’s iPhone. Police extracted data from the iPhone and made a digital copy. They then segregated the data that was relevant to the state court prosecution.

Separate from the state action, the Bureau of Alcohol, Tobacco and Firearms was investigating Hulscher on firearms-related charges. In preparation for trial, ATF saw in a National Crime Information Center report that Hulscher had been arrested by the local police. ATF then requested and got a complete digital copy off the iPhone data without a search warrant.

Hulscher moved to suppress the data copy in federal court. The government argued that the cell phone data was shareable between law enforcement agencies.

Two Approaches

In response, the court acknowledged a lack of precedent on how courts should treat digital copies of information, but noted two potential approaches.

"'[C]ourts can treat searches of copies just like searches of originals or else treat copies merely as data stored on government-owned property,” the court said, citing Orin Kerr’s Searches and Seizures in a Digital World, 119 Harv. L. Rev. 531, 562 (2005).

The court then explained that cell phone data isn’t the same as physical evidence, as shown in Riley v. California.

If the local police’s warrant wasn’t limited to the counterfeiting investigation, the warrant would have been an invalid “general warrant,” the court said.


The government argued that the court’s interpretation was “contrary to the nature of police investigations and collaborative law enforcement among different agencies.” But the court disagreed.

“The government’s position … overlooks the ultimate touchstone of the Fourth Amendment: reasonableness,” the court said.

The court said that if law enforcement agencies could save all unresponsive data from a cell phone for future searches that might assist in the investigation of unrelated charges, that policy would open the door to pretextual searches of cell phones.

“Under the government’s view, law enforcement officers could get a warrant to search an individual’s cell phone for minor infractions and then use the data to prosecute felony crimes,” the court said. “No limit would be placed on the government’s use or retention of unresponsive cell phone data collected under a valid warrant.”

The court suppressed the data obtained by ATF, finding that the review of the data constituted a search under the Fourth Amendment for which a warrant was required.

Amanda Kippley, of the Federal Public Defender’s Office in Sioux Falls, S.D., represented Hulscher.

Jennifer D. Mamenga, of the U.s. Attorney’s office in Sioux Falls, S.D., represented the government.

To contact the reporter on this story: Tera Brostoff in Washington at

To contact the editors responsible for this story: Carol Eoannou at; S. Ethan Bowers at

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