A five-day manhunt for the shooter who killed the top executive at the largest health-care insurance company in the United States came to an end Monday, after the suspect was spotted at a McDonald's, hundreds of kilometres from the crime scene, police said.

Local authorities arrested Luigi Mangione, 26, after a customer recognized him eating at the restaurant in Altoona, Pa., investigators announced Monday. Police said he was found carrying a gun matching the one used by the shooter who ambushed Brian Thompson, 50, outside a New York City hotel last week.

During a news conference on Wednesday, New York Police Department officials explained officers' efforts to catch Mangione, the circumstances of his capture and next steps for eventual prosecution.

Mangione faces several charges in Pennsylvania including forgery and carrying a firearm without a licence. He will eventually be extradited to New York to face charges there as well, police said.

Here's what we know so far.

What do police say Mangione had on him?

Mangione was found with a ghost gun — a weapon that can be made at home, and is nearly untraceable — and a suppressor. He also had multiple pieces of fake identification similar to those believed to have been used by the killer, officials said, as well as similar clothes.

One of those fake IDs was the same New Jersey ID the gunman used to check into a New York hostel before the shooting.

Authorities also found a handwritten, three-page document that they said spoke to Mangione's "motivation and mindset." Chief of Detectives Joseph Kenny later said it was clear from the document that Mangione had "some ill will toward corporate America," but did not further describe what was written.

Mangione also had a U.S. passport, but investigators don't believe he had plans to leave the country. Kenny said he did not have a criminal record.

Police said investigators are still combing through his online accounts for evidence. Kenny said they watched thousands of hours of video and reviewed hundreds of tips over the last five days, using drones, K-9 teams, scuba divers, fly-over canvasses and door-to-door work to find the suspect.

The suspect proved difficult to identify because he was masked in surveillance footage. Police released a pair of photos from the back of a taxi on Saturday showing more of his upper face. 

What do we know about Mangione?

Kenny said Mangione was born and raised in Maryland. He is from a prominent family in the state; one of his cousins is Nino Mangione, the Republican Maryland state legislator. 

Mangione went to high school at the all-boys Gilman School in Baltimore, where he was valedictorian in 2016. 

One of his classmates there, Freddie Leatherbury, called him a smart, friendly and athletic student, who came from a wealthy family, even by the private school's standards.

"He does not seem like the kind of guy to do this based on everything I'd known about him in high school," Leatherbury told The Associated Press. He hasn't spoken to Mangione since they graduated.

Mangione has a bachelor and a master's degree in computer science from the University of Pennsylvania and worked as a data engineer, according to Kenny. He also had ties to San Francisco and was most recently on record with an address in Honolulu, Hawaii. 

An account that appeared to belong to Mangione posted an online review in January of the Unabomber's manifesto, describing the document as revolutionary.

"When all other forms of communication fail, violence is necessary to survive," the Goodreads post read. His account has since been set to private.

"'Violence never solved anything' is a statement uttered by cowards and predators."

The Unabomber, Ted Kaczynski, planted bombs that killed three people and injured nearly two dozen more before he was arrested in 1996. In his manifesto, he blamed industrialization for destroying the natural environment. He was sentenced to several life terms in prison and died last year.

Online accounts appearing to belong to Mangione were flooded Monday with sympathy and praise from users. The most recent post on an Instagram account was filled with comments for police to release the "king" or the "GOAT" — the acronym for "greatest of all time."

Who was Brian Thompson?

Thompson was the CEO of UnitedHealthcare, the insurance arm of UnitedHealth Group that has about 50 million American customers. The unit saw $281.4 billion US in revenue in 2023, nearly double that of the next largest U.S. health insurer. 

Americans routinely pay more for health care than people in any other country.

Widespread rage at the state of the trillion-dollar industry found an unabashed outlet in Thompson's death in recent days.

The CEO was fatally shot from behind on Dec. 4 just before 6:45 a.m. ET in front of the New York Hilton Midtown, where he had been heading to attend an investors' conference.

WATCH | Thompson was shot in front of New York hotel: 

U.S. health insurance CEO shot dead in NYC in ‘targeted attack’

Brian Thompson, the CEO of a major American health insurance corporation, was shot and killed on a New York City sidewalk in what police call a ‘brazen, targeted attack.’ His masked killer escaped on an electric Citi Bike and is still at large.

A Facebook post from UnitedHealth Group mourning Thompson's death was met with tens of thousands of user reactions — the majority of which were the laughing emoji. Some wrote cutting posts pointing out that the $10,000 US reward for information on Thompson's killer was less than their annual insurance deductible, while others discouraged those with information on the shooter's whereabouts from phoning police. 

In a statement on Monday, a UnitedHealth Group spokesperson told the AP the company hoped "today's apprehension brings some relief to Brian's family, friends, colleagues and the many others affected by this unspeakable tragedy."

"We thank law enforcement and will continue to work with them on this investigation. We ask that everyone respect the family's privacy as they mourn."