High-tech drones were deployed, hundreds of hours of video footage were examined and state-of-the-art tools examined an “enormous amount” of forensic evidence. But when an arrest was made in connection with the high-profile killing of UnitedHealthcare CEO Brian Thompson, it came down to “good, old-fashioned police work,” authorities said.

Five days after Thompson was brazenly shot to death on a sidewalk in midtown Manhattan, 26-year-old Luigi Mangione was identified as a “person of interest” in the murder that, according to NYPD Commissioner Jessica Tisch, “captured the attention of the entire nation.”

Mangione, a former high school valedictorian with no known criminal history, was taken into custody Monday morning at a McDonald’s in Altoona, Pennsylvania, about 100 miles east of Pittsburgh, after an employee recognized him from surveillance photos obtained by the NYPD of the Shooter released had called 911.

He was subsequently charged with five crimes, including carrying a weapon without a firearms license, forging documents, falsely stating his identity to authorities and possessing “tools of crime,” according to a criminal complaint released Monday evening.

Altoona police officers, responding to the employee’s tip, confronted Mangione as he ate at the fast food restaurant, investigators said.

“Upon further investigation, officers recovered a firearm in his possession and a silencer, both consistent with the weapon used in the murder,” Tisch said.

Mangione — who grew up in Maryland and later lived in both San Francisco, California, and Honolulu, Hawaii — was charged with firearm possession, among other charges, but has yet to be charged with Thompson’s murder, Tisch clarified.

NYPD Chief of Detectives Joe Kenny described the gun allegedly found on Mangione as a “ghost gun” that appeared to have been made with a 3D printer and could fire 9mm cartridges.

Mangione was also in possession of a three-page, handwritten document that Tisch said “reflects both his motivation and his mindset.”

Kenny added that the document contained text that expressed “some antipathy toward corporate America.”

Several fake IDs and a U.S. passport were found on Mangione, Tisch said.

“In addition, a fake New Jersey ID was recovered that matched the ID our suspect used to check into his New York hostel prior to the shooting,” Tisch said.

Kenny said police did not identify Mangione by name before his arrest.

Tisch said police used drones, K-9 units and divers during the investigation. She said investigators relied heavily on the FBI’s expertise and technology in addition to its own intelligence and counterterrorism offices to solve the case.

“For just over five days, our NYPD investigators combed through thousands of hours of video footage, followed up on hundreds of leads and processed all forensic evidence, DNA, fingerprints, IP addresses and much more to tighten the net,” Tisch said. “Our investigators also went door-to-door interviewing potential witnesses, providing the good old-fashioned police work our investigators are famous for.”

The commissioner added: “It is this combination of old-school detective work and modern technology that has led to this result today.”

Thompson’s murder occurred around 6:40 a.m. Wednesday in front of New York’s Hilton Hotel, where the CEO was scheduled to attend a shareholder meeting.

The gunman, wearing a mask and hooded jacket, was captured on surveillance video ambushing Thompson from behind in what investigators called a “brazen and targeted shooting.”

Kenny said the big breakthrough in the investigation came just hours after the investigation began, when police obtained a surveillance photo of the suspect at a Starbucks on West 56th Street and 6th Avenue near the New York Hilton.

“There are numerous pivotal points in this case, namely the fact that we recovered a tremendous amount of forensic evidence and a tremendous amount of video. So I really couldn’t attribute it to one thing. “But if I had to, I would be releasing that photo,” Kenny said. “We took this photo and asked the public for help identifying this subject, and the public responded.”

Kenny said investigators spent hundreds of hours combing through “every video source we could collect.” Using video, investigators were able to track the killer from the crime scene as he fled on foot and by bicycle through Midtown Manhattan, Central Park and Upper Manhattan. Investigators even obtained a video of him shortly after he arrived in the city by bus.

Police subsequently released clearer images of the suspect, including one showing his face checking into a youth hostel in Upper Manhattan and a close-up of him wearing a mask in the back of a taxi.

“The images we shared with the public were widely disseminated and the tips we received led to the recovery of crucial evidence,” Tisch said, acknowledging the “instrumental role of the media and the public in this case.”

Tisch added: “We should never underestimate the power of the public to be our eyes and ears in these investigations.”

She said it was the third time in as many weeks that a tip from the public had led to an arrest in a high-profile case, including a triple stabbing in Manhattan and a series of gunpoint robberies in Queens involving a police officer There was a shot present.

Kenny said the investigation is far from complete as investigators continue to examine whether the shooter had help.

“We believe our investigation at this point indicates that he acted alone,” Kenny said.

Looking forward, Tisch said, “Working with the Manhattan District Attorney’s Office, we will seek to have him extradited back to New York so he can be charged here.”