In the days before Tuesday’s Brooklyn shooting rampage that left 10 people shot and 19 others injured, the alleged shooter traveled back and forth between New York City and a Philadelphia apartment and storage unit, where he had a cache of weapons and ammunition, court records show.

Frank James, who is now being held without bail for allegedly firing 33 shots in a subway train, had rented both a storage unit and a van from a Philadelphia U-Haul facility, as well as an apartment in the city, the criminal complaint shows.

The owner of the Philadelphia apartment told The Inquirer on Thursday that although she had no issues with tenants previously, she’s now worried about the next person who might book a stay.

“I have to think twice about it,” said Janet McDaniel. “It’s really been good with no real issues. But this time it’s a little bit different. You don’t know who. You just don’t know.”

A discarded receipt found on the subway platform where the shooting occurred led law enforcement officials to the storage facility James, 62, rented in Philadelphia. Inside the unit, investigators found 9mm ammunition, a threaded 9mm pistol barrel that allows for a silencer or suppressor to be attached, targets, and .223-caliber ammunition that is used with an AR-15 semiautomatic rifle.

» READ MORE: Brooklyn subway attack suspect ordered held without bail

Agents also searched the apartment he rented on the 1800 block of Ontario Street in the Nicetown-Tioga section of the city. The complaint says agents found more weapons and ammunition — an empty magazine for a Glock handgun, a stun gun, a high-capacity rifle magazine, and a blue smoke canister.

The amount of ammunition found, particularly ammunition used with an AR-15, pointed to James having access to additional firearms and led to a federal agent requesting a no-knock warrant because of the danger James potentially posed.

From March 28 to April 10, James had taken around 21 Lyft rides to and from the apartment he had rented. According to the management company, James had rented the apartment for 15 days, starting March 28 and ending April 12, the day of the shooting.

According to the complaint, James took a Lyft ride to the storage unit at 6:17 p.m. Monday.

Since 2016, McDaniel has owned the apartment building where James rented the first floor and basement units through the Evolve app, she said. James was paying $80 a night for the rental.

McDaniel said she and James had only one real conversation during his stay, when he called to let her know that the cable was not working, but he wasn’t present when she went to the unit to fix it.

On Tuesday night, just hours after the shooting, the FBI called McDaniel to question her about James, she said. McDaniel gave the FBI entry codes to access the building.

On Wednesday morning, the second-floor tenant called McDaniel to let her know that a SWAT team had set up outside, ready to breach the apartment.

In addition to the weapons found at the storage locker and the Ontario Street apartment, the New York Police Department recovered a semiautomatic handgun, three extended magazines, a hatchet, fireworks, and gasoline at the scene of the shooting. At a Wednesday afternoon briefing, John Devito, the ATF special agent in charge of the New York field division, said that the gun James allegedly used in the shooting was 16 years old and James had purchased it legally in Ohio in 2011.

Despite some reports, the FBI had not been investigating James prior to the shooting, said Michael J. Driscoll, the assistant director in charge of the FBI’s New York office. James had ties to Wisconsin, Ohio, Pennsylvania, and New Jersey, and had three arrests in New Jersey for charges including trespassing, larceny, and disorderly conduct, officials said Wednesday.

The FBI Philadelphia field office declined to comment on the case Thursday.

James was arrested in the East Village section of New York on Wednesday afternoon, after a Crimestoppers tip notified police.

It was later reported that James had called police to turn himself in. He was taken into custody without incident.

At James’ bail hearing, prosecutors told a judge he terrified New York City, detailing his alleged rampage.

James spoke only to answer “yes” to standard questions during the brief proceeding in a federal court in Brooklyn. Prosecutors portrayed James as a person intent on violence, who talked about shooting and killing people in several YouTube videos.

“The defendant terrifyingly opened fire on passengers on a crowded subway train, interrupting their morning commute in a way the city hasn’t seen in more than 20 years,” Assistant U.S. Attorney Sara K. Winik said Thursday. “The defendant’s attack was premeditated, was carefully planned, and it caused terror among the victims and our entire city.”

James had enough guns and ammunition in the Philadelphia storage unit and apartment to carry out more attacks, prosecutors wrote in their detention memorandum.

His lawyer, Mia Eisner-Grynberg, agreed to his being held without bail for now but could still seek bail later on.

James didn’t respond to shouting reporters Wednesday as he was led from a police precinct into a car headed for a federal detention center.

Staff writer Jeremy Roebuck and the Associated Press contributed to this article.