The US Marshals Services has intervened in a dispute between a Florida police department and the ACLU, with the Marshals sweeping in at the last minute to seize controversial cell phone records before the ACLU was able to review them.

Earlier this year the Florida chapter of the American Civil Liberties Union filed a lawsuit against the Sarasota Police Department in an attempt to compel them to turn over records on the police’s use of its “Stingray” devices.

The powerful Stingray equipment has drawn the ire of civil liberties advocates nervous about its ability to essentially act as a fake cell tower and collects information from each of phone that connects to it.

The ACLU, which asserts that the Stingray enables the “electronic equivalent of dragnet ‘general searches’ prohibited by the Fourth Amendment,” convinced the court to force the Sarasota police to make the documents available for review.

ACLU staff attorney Nathan Freed told Wired that the US Marshals sent an agent from the Tampa area to Sarasota to pick up the documents so the police would be unable to disclose them.

Wessler described the incident as “truly extraordinary and beyond the worst transparency violations” the ACLU has seen regarding use of the Stingray.

“This is consistent with what we’ve seen around the country with federal agencies trying to meddle with public requests for Stingray information,” he said, adding that officials have used the Homeland Security Act in the past to keep the documents under lock and key. “The feds are working very hard to block any release of this information to the public.”

The ACLU is working to obtain the records in question because the organization discovered that a Florida police detective was earned permission to use the Stingray by filing an application under Florida’s “trap and trace” statute, which gives police more leeway than the usual probable-cause warrant.

Wired explained that, while trap and trace orders are used to obtain information such as the time and duration of a call, a Stingray would have given the Florida detective the ability to track the location of cell phones. The ACLU has argued that the Stingray constitutes a more invasive device than the kind currently allowed under the trap and trace statute.

“In this case, police used two versions of the Stingray – one mounted on a police vehicle, and the other carried by hand,” the civil liberties group wrote. “Police drove through the area using the vehicle-based device until they found the apartment complex in which the target phone was located, and then they walked around with a handheld device and stood at ‘every door and every window in that complex’ until they figured out which apartment the phone was located in. In other words, police were lurking outside people’s windows and sending powerful electronic signals into their private homes in order to collect information from within.”

The Marshals asserted that because the detective who used the Stingray was deputized as an agent, the documents actually belong to the Marshals service.

Not all police departments are authorized to use the Stingray, although the Sarasota cops have revealed that they have employed the technology no less than 200 times in the years between 2007 and 2010. Even more alarming, from the ACLU’s point of view, is that each of the 200-plus incidents came without a judge’s permission. They were reportedly able to do so by signing a non-disclosure agreement with the Stingray manufacturer.

The ACLU now believes that the dozens of US police departments allowed to use Stingrays have signed non-disclosure agreements with the Florida-based Harris Corporation and are thus subverting the need for judicial permission. ACLU attorneys explained in a blog post Tuesday, though, that the Marshals’ sudden decision to supersede the Sarasota police and take the records will prevent the situation from being resolved soon.

“We’ve seen our fair share of federal government attempts to keep records about Stingrays secret, but we’ve never seen an actual physical raid on state records in order to conceal them from public view,” they wrote. “When police engage in invasive tracking of our locations and communications, it is crucial that the public have access to accurate information so it can participate in an informed debate.”