Oregon sought and won approval for more delayed-notice search warrants than any other state except Illinois, according to the most recent annual federal court data available.

Oregon had 851 from Oct. 1, 2015, through Sept. 30, 2016.

As across the nation, most of the warrants in Oregon came in drug cases.

Here, the majority sought to collect geographic location data from a suspect's mobile phone, a senior drug prosecutor said.

Nationally, the next most frequent request was for fraud.

Federal officers must show probable cause that the property targeted for a search holds evidence of an alleged crime. That's required by the Fourth Amendment, which protects private citizens from unreasonable searches and seizures.

Judges must believe that the delay would protect someone's safety, stop someone from fleeing or prevent someone from destroying evidence or otherwise jeopardizing an investigation.

Under federal statute, the target of the warrant should get notice of the search and any seizure within a "reasonable period'' not to exceed 30 days. With a judge's approval, the law also allows federal agencies to ask for extensions of up to 90 days to further delay notice, "unless the facts of the case justify a longer period of delay.''

According to the latest data, federal officials in Oregon made 385 requests for delayed-notice warrants, plus 466 extension requests. Judges rejected none of the requests.

The average delay in Oregon was 106 days, exceeding the average national delay of 84 days with such warrants, according to the data.

Overall, the nation's federal judges approved 9,140 delayed-notice warrants and another 6,024 extensions in the same period.

Judges for decades have had the power to allow officers to delay notice of a search warrant, but the USA Patriot Act created explicit authority for federal investigators and prosecutors to seek permission while setting certain standards.

Oregon's federal drug prosecutors don't put much weight on the court data, suggesting there are discrepancies among federal districts on how they handle delayed-notice warrants.

For example, federal prosecutors in Oregon started pursuing the warrants for geolocation data for cellphones only about three years ago, and those make up about 80 percent of their requests, said Kevin Sonoff, spokesman for the Oregon U.S. Attorney's Office.

That switch has elevated Oregon's numbers, they believe.

Previously, they had submitted an application and court motion for the phone geolocation data, which requires a significantly lower standard of proof -- "reasonable grounds'' to believe the communications are relevant to a criminal investigation.

"We wanted to take a more conservative approach,'' Sonoff said. "We think that's why these numbers for Oregon are higher. Other districts might still be using a motion and not a search warrant to obtain the same data.''

Phones regularly ping cell towers to register their position, producing location histories and other records. Such historical data is collected by phone companies. Investigators also can request real-time updates from telephone companies or use a device to intercept phone signals and collect geolocation data by pretending to be a cellphone tower.

The U.S. Justice Department advised prosecutors in 2016 to get warrants for real-time tracking of phone locations, but not for historic data from cell towers.

Sonoff estimated that less than 10 of the delayed-notice warrants during the 2015-2016 period were for a property, such as a storage unit.

-- Maxine Bernstein

mbernstein@oregonian.com

503-221-8212

@maxoregonian