How the New York City subway shooting suspect was captured

Brooklyn subway shooter suspect Frank James, was arrested within 30 hours after the incident through a combination of on-the-ground detective work, technology and possibly a tip from the fugitive himself, investigators said.

"We were able to shrink his world, quickly. There was nowhere left for him to run," New York Police Department Commissioner Keechant Sewell said at a press conference Wednesday afternoon.

Officers got their first lead soon after the incident at the crime scene, the 36th Street subway station in Sunset Park, Brooklyn, where several eyewitnesses filmed and photographed James.

Police said the suspect also left behind key pieces of evidence that helped them track his movements before and after the incident -- a 9 mm Glock allegedly used in the shooting, his coat, a bag filled with fireworks and James' credit card.

James used the credit card to rent a U-Haul van that was discovered parked five miles southeast of the station, police said. Officers recovered the vehicle later in the evening.

James legally purchased the gun in Ohio in 2011, according to the NYPD. The Bureau of Alcohol, Tobacco, Firearms and Explosives is currently looking over data related to the gun, according to the agency.

Cameras were not working inside the 36th Street subway station, but he was filmed entering the subway station near where the van was found, according to investigators. He was also spotted at the 7th Avenue station in Park Slope, roughly three miles north of the crime scene, less than 30 minutes after the shooting, police said.

James fled the scene in an R train from the 36th Street station, police said.

While investigators continued to probe through clues, including James' social media posts where he ranted against New York City Mayor Eric Adams, police released his photo to the public Tuesday night and named James as a "person of interest."

"That was a critical effect on raising the kind of public awareness," John Miller, the NYPD deputy commissioner for intelligence and counterterrorism, said at Tuesday's news conference.

A cellphone alert with James' description went out to New York City residents at 10:21 a.m. Wednesday, just hours after the police officially identified him as a suspect.

The NYPD said they received a Crime Stoppers tip a few hours later from some claiming James was inside a McDonald's in Manhattan's Lower East Side. The tipster may have been James himself, according to sources.

“I think you’re looking for me. I’m seeing my picture all over the news, and I’ll be around this McDonald's,” one of the tipsters reportedly said, according to sources.

An NYPD official said police are reviewing the 911 call.

When officers responded to the McDonald's, James was nowhere to be seen, so officers drove around the neighborhood, according to the NYPD.

Around 1:45 p.m. officers found James in the East Village neighborhood of Manhattan and arrested him without incident, according to police.

The FBI, ATF and other federal law enforcement agencies said they are still going through evidence and clues related to the shooting.

ABC News' Aaron Katersky and Mark Crudele contributed to this report.