Crime Reporter

In the days after the shooting, the NYPD deploys an army to Manhattan, including drones, police, scuba divers, trying to find everything they possibly can. Right at dusk on Friday, police in Central Park find what they believe is the shooter's backpack. There's a jacket, and there's Monopoly money.

People online are falling in love with this suspect, and some of them are even making TikToks using the Britney Spears song Criminal.

The unprecedented explosion really showed the level of true public antipathy toward not just corporate America, but the health insurance industry.

The manhunt went on for six days without any success. So pretty quickly, a reality is creeping in that this shooter could be anywhere.

Sixth Avenue this time of year. You probably don't have a more trafficked or highly populated part of Manhattan or New York, except for Times Square. We're talking about a couple of blocks away from Rockefeller Center with the famous Christmas tree. Right near there, you have Radio City Music Hall, famous for its Christmas show. Hilton itself is a busy, busy place.

Luigi Mangione's grandfather, Nicholas, really is an American rags to riches story. He fought against anti-Italian discrimination in Baltimore and built a really successful portfolio of businesses that has made his family prominent and wealthy.

That morning, UnitedHealthcare was having an investor conference.

After graduation, Luigi Mangione appears to have gone to California. He was working in tech. He worked as a data engineer.

At that point, he's into experiencing nature, healthy living. Of course, he's showing off his body on social media.

He commented on the Unabomber Manifesto, and at a certain point, he refers to him in a way that people have taken as almost sympathetic.

He posted online an image that is believed to be an x-ray of his own spine with four surgical screws in his spine that it was a fusion surgery, which is often done on people who suffer extreme back pain. But UnitedHealthcare says that he was never a customer of their insurance company.

In the six months before the shooting, importantly, it seems that Luigi kind of went dark. He didn't really post online for that period of time.

The NYPD Intelligence Bureau put together a confidential assessment that ABC News has obtained. They believe that in his mind, this was quote unquote, a symbolic takedown of the healthcare insurance industry.

Allegedly, it shows that the killing of Brian Thompson was premeditated, it was planned, it was strategic.

In addition, he's now facing federal criminal charges. and they carry with them the possibility of the death penalty.

I think about the irony. Brian Thompson is the CEO of UnitedHealthcare. He gets killed in cold blood in Manhattan. And in the immediate aftermath, as they're planning funeral and succession and business issues, they have to worry about putting fencing up around their headquarters because of the threats.

After he gets the water bottle and the kind bar from the Starbucks, he takes position and then holds up in the pre-dawn dark and he sees Brian Thompson.

You see Brian Thompson walking past the area where the shooter is located. The shooter comes up behind him. It appears that it may be 10 or 12 feet behind Brian Thompson. The shooter fires three times. It seems that the gun jammed several times in between the shots. And that's going to be very, very important down the road for police investigating the crime.

You see a bystander run out of the frame in the other direction. Brian Thompson is on the floor.

When detectives went back and started looking at these images frame by frame over and over again, they noticed a couple of things. First of all, they noticed how far away the shooter was from Brian Thompson. Detectives were saying to us that if this had been somebody who was really a trained assassin, he wouldn't have fired from 10 or 12 feet away. He would have fired from five or seven feet away.

He took off before he made sure that his victim was dead. And trained assassins would not do that.

Police quickly get into Brian Thompson's hotel room. They get his phone. They're trying to see, is there somebody out there that might have a grudge or a vendetta against Thompson? Did he owe money to people? Was there some sort of a drug thing, an alcohol thing? All these things are quickly being cycled through. And pretty fast, the police determine there's none of that.

Investigators were telling us that they believed in theory, without having a ton of evidence yet, that this felt to them like this was a shooting motivated by Brian Thompson's work.

And that has an eerie echo to a book critical of the insurance industry, talking about the tactics that health insurance companies use to either refuse to pay claims, to slow paying for claims.

a corporation. Almost as soon as it's confirmed that Brian Thompson is dead, social media explodes, and in a really unanticipated, unpredicted kind of way.

This case was the source of unbelievable public fascination. It had all of the ingredients. First of all, it's a midtown Manhattan murder. Then you have a manhunt. And it just builds and builds and builds. And the police are starting to put out images and asking for the public's help.

So the suspect shoots Brian Thompson, and then he takes off.

So the shooter is able to basically evade surveillance for a period of time. He's gone.

He comes out of Central Park at 77th on the bike. We then see him on 86th. No bike, no backpack. He gets into a taxi.

And the first images have his face, but not a full face. And that adds to additional fascination. And all of a sudden, it's like the masked gunman. So pretty quickly, the question is, are they going to find him today?

We're talking about a bus station that's right up next to the busiest bridge in the country.

At the same time, in Midtown, The investigation and the response to this crime is picking up.

In those first few minutes, all the police really have to go on is that a crime was committed. And then, little by little, more information is added to that. But all that while, the shooter is getting farther and farther away from the scene of the crime.