As tensions eased and protests continued this past weekend in Baltimore, a small squadron of aircraft circled neighborhoods affected by the riots and other violence of April 27—providing Baltimore City Police with an eye in the sky to monitor the protests and other "possible criminal activity," as an FBI official told the Washington Post.

These aircraft (or at least some of them) were part of the FBI's secret surveillance air force—small planes with sensors perfected for battlefield intelligence in Iraq and Afghanistan that have quietly seen service all over the country. The aircraft, equipped with high-definition day and night surveillance systems, gave police a way to spot curfew-breakers on the streets from the sky.

In a response to an inquiry from Ars, an FBI spokesman said, "During the recent unrest, the FBI provided aircraft to the Baltimore Police Department for the purpose of providing aerial imagery of possible criminal activity. The aircraft were specifically used to assist in providing high-altitude observation of potential criminal activity to enable rapid response by police officers on the ground." The spokesman added that the flights "were not there to monitor lawfully protected first amendment activity, and any FBI aviation support to a local law enforcement agency must receive high level approvals.”

Capt. Eric Kowalczyk, a Baltimore City Police Department spokesman, told Ars that the department had received multiple media requests for information on the flights and would be making a statement on the use of the aircraft this afternoon through social media. That statement has not yet been posted, and Ars will update this story when it becomes available.

While the FBI acknowledges the existence of its surveillance fleet, the ownership of these small, unmarked aircraft is well-obscured for operational security reasons. They seldom post flight plans, with records for the aircraft seen over Baltimore having only reported flights last month in Virginia and Florida. The planes, some of which were spotted flying low over the city by residents and tracked by flight watchers on the Internet, are registered to a collection of aircraft leasing corporations and shell companies to hide their true purpose from prying eyes. The exact number, basing location, and types of aircraft operated by the FBI's Surveillance and Aviation Branch is classified.

On April 29, a Cessna 206H registered to National Aircraft Leasing Corporation circled overhead for hours at about 3,500 feet, flying repetitively over western Baltimore. On the nights of April 30, May 1 and May 2, another aircraft, a Cessna Model 182T registered to a company named NG Research in Bristow, Virginia, flew over the same areas at a similar low altitude.

Also on May 1 and May 2, an unidentified Cessna Citation V jet made similar nighttime flights, orbiting Baltimore at the relatively low altitudes (for a jet aircraft) of 6,400 and 9,400 feet, based on records from Flightradar24.











There had been speculation that these aircraft carried advanced digital surveillance gear from Persistent Surveillance Systems, a company that has previously conducted testing in Baltimore as well as Dayton, Ohio and other cities. But given the time of day, and the FBI's acknowledgement of its aircraft support for Baltimore police, these aircraft likely carried stablized forward looking infrared and electro-optical sensor systems similar to those purchased by the FBI in 2010 from L-3 WESCAM explicitly for mounting on Cessena aircraft—and from the same family of hardware that the Army has been evaluating for the Apache attack helicopter. These sensor-equipped planes have shown up all over the country in the past few years, apparently as part of law enforcement operations.



The FBI has been using aircraft for surveillance since 1938 (when a plane was used to spot the payoff package for an extortion attempt as it was thrown from a train), and infrared sensors have been used since at least the 1990s. By 2003, the FBI had over 80 aircraft, including a handful of "Nightstalker" infrared surveillance planes.

The latest aircraft could also carry electronic eavesdropping gear, including "Stingray" or "dirtbox" cell phone interception systems. An FBI Joint Terrorism Task Force team recently took an FBI aircraft with optical and radio sensors to the UK and flew accompanied by RAF pilots, trying to intercept phone calls from individuals tied to the British member of ISIS known as "Jihadi John."