Police arrested a 鈥渟trong person of interest鈥� Monday in the brazen Manhattan after a quick-thinking McDonald鈥檚 employee in Pennsylvania alerted authorities to a customer who was found with a weapon and writings linking him to the ambush.

The suspect, identified by police as 26-year-old Luigi Nicholas Mangione, had a gun believed to be the one used in last Wednesday鈥檚 shooting of , as well as writings suggesting anger with corporate America, police said.

Mangione was taken into custody about 9:15 a.m. after police got a tip that he was eating at a McDonald鈥檚 in Altoona, Pennsylvania, police said.

鈥淗e is believed to be our person of interest in the brazen, targeted murder of Brian Thompson,鈥� NYPD Commissioner Jessica Tisch said.

Mangione had clothing and a mask similar to those worn by the shooter and a fraudulent New Jersey ID matching one the suspect used to check into a New York City hostel before the shooting, Tisch said.

NYPD Chief of Detectives Joseph Kenny said Mangione was born and raised in Maryland, has ties to San Francisco and a last known address in Honolulu, Hawaii. A message left Monday with a Philadelphia-area phone number connected to Mangione was not immediately returned.

He was being held in Pennsylvania on gun charges and eventually will be extradited to New York to face charges in connection with Thompson鈥檚 death, Kenny said.

Police found a three-page document with writings suggesting that Mangione had 鈥渋ll will toward corporate America,鈥� Kenny said.

The handwritten document 鈥渟peaks to both his motivation and mindset,鈥� Tisch said.

Mangione had a ghost gun, a type of weapon that can be assembled at home from parts without a serial number, making them difficult to trace, investigators said.

鈥淎s of right now the information we鈥檙e getting from Altoona is that the gun appears to be a ghost gun that may have been made on a 3D printer, capable of firing a 9 mm round,鈥� Kenny said.

Officers questioned Mangione, who was acting suspiciously and carrying multiple fraudulent IDs, as well as a U.S. passport, Tisch said. Officers found a suppressor, 鈥渂oth consistent with the weapon used in the murder,鈥� the commissioner said.

NYPD detectives and staff from the Manhattan district attorney鈥檚 office were traveling to Altoona to interview Mangione, Kenny said.

Thompson, 50, was killed last Wednesday as he walked alone to a hotel, where UnitedHealthcare鈥檚 parent company, UnitedHealth Group, was holding its annual investor conference, police said.

The shooter appeared to be 鈥渓ying in wait for several minutes鈥� before approaching the executive from behind and , police said. He used a 9 mm pistol that police said resembled the guns farmers use to put down animals without causing a loud noise.

Mangione attended an elite Baltimore prep school, graduating as valedictorian in 2016, according to the school鈥檚 website. In his graduation speech, he talked about his classmates鈥� 鈥渋ncredible courage to explore the unknown and try new things.鈥� He praised their collective inventiveness and pioneering mindset.

In the days since the shooting, police turned to the public for help by releasing a collection of nine photos and video 鈥� including footage of the attack, as well as images of the suspect at a Starbucks beforehand.

On Monday, police credited news outlets for disseminating the images and the tipster for recognizing the suspect and calling authorities.

鈥淟uckily, a citizen in Pennsylvania recognized the subject and called local members of the Altoona Police Department responded to the call, and based on their investigation, they notified the NYPD,鈥� Kenny said.

Photos taken in the lobby of a hostel on Manhattan鈥檚 Upper West Side showed the suspect grinning after removing his mask, police said.

Investigators earlier suggested the gunman may have been a disgruntled employee or client of the insurer. Ammunition found near Thompson鈥檚 body 鈥渄elay,鈥� 鈥渄eny鈥� and 鈥渄epose,鈥� mimicking a phrase used by .

The gunman concealed his identity with a mask during the shooting yet left a trail of evidence, including a backpack he ditched in Central Park, a cellphone found in a pedestrian plaza and a water bottle and protein bar wrapper that police say he bought at Starbucks minutes before the attack.

On Friday, police that they say the killer discarded as he fled from the crime scene to an uptown bus station, where they believe he left the city on a bus.

using surveillance video, investigators say the shooter fled into Central Park on a bicycle, emerged from the park without his backpack and then ditched the bicycle.

He then walked a couple blocks and got into a taxi, arriving at at the George Washington Bridge Bus Station, which is near the northern tip of Manhattan and offers commuter service to New Jersey and Greyhound routes to Philadelphia, Boston and Washington, Kenny said.

The FBI announced late Friday that it was offering a $50,000 reward for information leading to an arrest and conviction, adding to a reward of up to $10,000 that the NYPD offered.