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FLIR Helped Catch a Murderer — but Not Without a Delay

The U.S. Drug Enforcement Administration’s FLIR technology helped catch Danilo Cavalcante after his escape from prison in Pennsylvania, but severe weather rendered the tool useless during a critical part of his capture.

FLIR Camera--Collection_1200_canvas.jpg
A forward-looking infrared, or FLIR, camera.
Drug Enforcement Administration Museum
The nearly two-week manhunt for a convicted murderer who escaped from a Pennsylvania prison came to a non-violent conclusion, in part thanks to FLIR and night vision technology.

However, limitations to the technology also caused an hourslong delay in the armed and dangerous man’s capture.

Danilo Cavalcante first escaped from Chester County Prison shortly after his conviction for killing his former girlfriend at the end of August.

Pennsylvania state officials praised FLIR technology mounted on a Drug Enforcement Administration (DEA) Air Wing for locating Cavalcante in the vast and rugged terrain of a perimeter they had established through surveillance images and witness sightings of the suspect.

After using the technology to identify Cavalcante’s position, U.S. Border Patrol BORTAC K-9 Yoda performed a “bite and hold” maneuver that allowed officers to arrest the subdued killer and get him back into custody.


FLIR, or forward-looking infrared, cameras make pictures from heat, and can create an image without having to scan the scene with a moving sensor. Product manufacturer Teledyne FLIR reports standard cameras can detect temperature differences for temperatures between -4 to 3,632 degrees Fahrenheit.

According to FLIR manufacturer Infiniti Electro-Optics, the technology is immune to changes in light. However, it can’t see through glass, doesn’t show visible contrast, and while it can detect humans, it’s not effective to identify them.

FLIR is not new; law enforcement agencies recognized the value of the technology more than 30 years ago. FLIR is often used by the DEA to identify buildings that house marijuana crops and other drug processing labs.


At a Chester County press conference, law enforcement leaders detailed how FLIR technology was used in the escaped murderer’s capture.

A burglary alarm activation just after midnight on Sept. 13 drew their attention to a smaller section of their search perimeter. Then, a DEA Air Wing with FLIR technology picked up a heat signal.

“Tactical teams began to converge in the location where the heat source was moving; unfortunately, we had a weather system that came in and we had lightning that was flashing all around and it caused the aircraft to have to depart the area,” said Lt. Col. George Bivens, deputy commissioner of operations for the Pennsylvania State Police. “Tactical teams made a decision to secure the area as best they could and hold it until the storm — until we could bring additional resources in and bring aircraft back overhead to ensure that we did not have an issue with an escape.”

The mission resumed when the weather cleared several hours later. FLIR technology again identified the heat source, and Pennsylvania State Police and U.S. Border Patrol moved in on the suspect, releasing the K-9 to capture him when he attempted to escape.

Bivens credited FLIR with giving law enforcement the ability to surprise the suspect, despite the delay.

“Everything isn’t scripted and doesn’t go perfectly, it’s just another challenge,” said Bivens. “We simply had to adapt, so we secured that inner perimeter while always keeping our outer perimeter secure so that if he did manage to get out of that inner, we would box him in the outer perimeter again.”


While the technology in this case belonged to the DEA, FLIR is used by some state and local governments.

In Washington state, the King County Sheriff’s Department has permanently mounted FLIR technology on its Guardian One air unit. The aircraft is can be used by other agencies in the county when available; it was deployed in Seattle 45 times in 2018.

The most common types of crimes in which Guardian One was used in the city were robberies (eight), automotive theft and recovery (seven), assaults (six) and burglary (six). FLIR has also been used in Seattle for cases involving domestic violence, kidnapping/abduction, traffic violations, warrant services, weapons and missing and runaway persons.

The ACLU raised concerns about aerial surveillance in 2015, after Freedom of Information Act requests revealed FLIR technology was mounted on an FBI aircraft that monitored protests in Ferguson, Mo., and Baltimore following the deaths of Michael Brown and Freddie Gray.

“There undoubtedly are times when aerial surveillance is an appropriate law enforcement tool for public safety or investigative purposes,” wrote Nathan Freed Wessler, deputy project director for the ACLU Speech, Privacy, and Technology Project. “But it is essential that accurate information about such surveillance be available to the public, and that strict rules be in place to protect against unjustified mass surveillance or warrantless collection of private information.”
Nikki Davidson is a data reporter for Government Technology. She’s covered government and technology news as a video, newspaper, magazine and digital journalist for media outlets across the country. She’s based in Monterey, Calif.