What is FLIR, the heat-seeking tech police used to apprehend fugitive Danelo Cavalcante?

Pa. police captured convicted killer Danelo Cavalcante early Wednesday morning after a two-week manhunt using cameras that provide thermal imaging.

After a 13-day manhunt that involved hundreds of law enforcement officers, fugitive Danelo Cavalcante was apprehended in southeastern Pennsylvania, police announced Wednesday morning. In large part, they were able to track him down using heat-seeking technology known as FLIR.

Pennsylvania State Police Lt. George Bivens said at a news conference that after a burglar alarm at a residence in South Coventry Township went off shortly after midnight on Wednesday morning, an aircraft using FLIR picked up a heat signal nearby. After waiting out a rainstorm, a tactical team was able to zero in on the thermal image.

“It played out very quickly then,” Bivens said.

The capture of Cavalcante, a convicted killer, ended what was a tense couple of weeks for the region. He escaped from Chester County Prison in West Chester, Pa., on Aug. 31, leading nearby schools to close and residents to shelter in place out of precaution.

Escaped fugitive Danelo Cavalcante
Escaped fugitive Danelo Cavalcante being taken into custody by law enforcement officers on Wednesday. (Pennsylvania State Police/Handout via Reuters)

Read more on Yahoo News: Pennsylvania manhunt: Police finally capture Danelo Cavalcante 2 weeks after prison escape

What is FLIR?

FLIR, which stands for Forward Looking Infrared, refers to the technology used to create an infrared image that portrays objects using their radiated heat, according to Infiniti Electro-Optics, a leader in infrared electro-optics and video surveillance technologies.

Thermal imaging, which is a type of infrared imaging, uses cameras that “see” heat instead of light and picks up on any object warmer than absolute zero (-273°C/-459°F). The technology allows an operator to see in complete darkness, unfavorable weather and through air pollutants such as the smoke from fires.

An example of the FLIR thermal imaging used to track missing people. (Teledyne FLIR)
An example of the FLIR thermal imaging used to track missing people. (Teledyne FLIR)

Adam Wandt, an attorney and expert in policing technology, told Yahoo News that FLIR allows humans to see beyond the red in the rainbow spectrum, which includes infrared electromagnetic energy that comes from heat.

“What humans are able to see is limited,” said Wandt, an assistant professor at John Jay College of Criminal Justice, who uses FLIR as a teaching tool. “So if we are looking for anything in a dense wooden population or a field, FLIR allows us not just to see objects. It allows us to see heat, including where that heat is and where it was because they’ve left.”

Developed in the early 1960s and used for surveillance and military operations, FLIR technology has been leveraged to work across a number of industries from developments in science to spotting unwanted moisture during building inspections to firefighting and more.

Read more on Yahoo News: The daughter of the woman killed by Pennsylvania prison escapee Danelo Cavalcante told police he said he was going ‘to do something bad’ to them, via CNN

FLIR Star SAFIRE imaging systems
FLIR imaging systems are fielded on fixed-wing aircraft and helicopters worldwide. (Business Wire via AP)

The Pennsylvania state police aircraft utilizing FLIR technology was able to pick up Cavalvante’s heat signal while it was still dark outside and allowed authorities to secure a smaller area around him without being noticed until it was too late for the suspect.

Bivens said that Cavalcante didn’t realize he was surrounded and tried to escape before a dog subdued him, leaving a minor bite wound on his scalp.

FLIR controversy

In 1991, FLIR was used to arrest and convict a man accused of growing marijuana inside his home. Though federal agents could not get inside the home, they used an infrared camera to identify suspected heat lamps growing dozens of marijuana plants. In a landmark ruling 10 years later, however, the Supreme Court ruled that using an infrared camera without a warrant constituted an unreasonable search barred by the Fourth Amendment.

“To withdraw protection of this minimum expectation would be to permit police technology to erode the privacy guaranteed by the Fourth Amendment,” the 5-4 opinion written by then-Justice Antonin Scalia stated.

Pennsylvania State Police Lt. Col. George Bivens, right, and Pennsylvania Gov. Josh Shapiro at a press conference
Pennsylvania State Police Lt. Col. George Bivens, right, and Pennsylvania Gov. Josh Shapiro at a press conference after the capture of Cavalcante. (Ryan Collerd/AFP via Getty Images)

Wandt notes that while it is inevitable that some people will abuse the abilities of FLIR technology, in this case, the courts upheld individual rights.

“There’s a downside to people using any technology, including cameras,” he said. “Could the government be intrusive with it? Yes. But are there Supreme Court cases protecting Americans? Yes. As with any technology, there’s the need to use it responsibly no matter what it is.”

On Wednesday, because of FLIR, communities across Pennsylvania are now breathing a sigh of relief.

“Our nightmare is finally over,” Chester County District Attorney Deb Ryan said in a statement. “And the good guys won.”