Last summer, I interviewed dozens of the ironworkers who were working around the clock to turn One World Trade Center into the tallest building in the western hemisphere. This week, one of those workers was arrested for parachuting from the top of the tower he helped build.

Jim Brady, 32, was typical of those who make their living guiding steel beams into place hundreds of feet up in the sky: intense, physically-imposing, more inclined to adventure than introspection. When we spoke on the 102nd floor of 1 WTC, the building had topped out at 104 floors and the spire, which climbed to the symbolic height of 1,776 ft., had already been set. The end was in sight and Brady and his fellow ironworkers from Local 40 were a bit more open to reflection than usual.

“Whenever I see it, I’m like, ‘F—in’ A, man, the thing’s f—in’ huge!” Brady said. “And we were up there.”

For nearly everyone who helped build 1 WTC, the job had the potential to serve as a daily reminder of the September 11, 2001 terrorist attacks. Brady, who says he was working construction on Long Island at the time, visited Lower Manhattan and lent a hand two days later. But the demands of the job—Brady had spent four years on the site as a connector, linking the massive pieces of steel together—kept the emotional weight at bay.

“You just get in the groove of things,” Brady told me. “You don’t get to think about too much else.”

A few months later, Brady was one of four ironworkers who helped TIME’s Jonathan Woods and Gigapan’s Michael Franz take a 360-degree interactive photo from 1 WTC’s spire. Two days after that, Brady and two other men BASE jumped from 1 WTC in the middle of the night and parachuted onto West Street. They filmed the entire thing — and likely would have gotten away with it had one of them not been spotted by a nearby security guard.

Jim Brady, far right, and TIME's Jonathan Woods, second from right, on the spire of 1 World Trade Center Doug Holgate — New York on Air for TIME

In February, Brady, along with Marko Markovich, 27, Andrew Rossig, 33, and Kyle Hartwell, 29, (who acted as a look-out on the street, according to police), contacted lawyers after learning that they were being investigated. Andrew Mancilla, Brady’s lawyer, says the men were preparing to turn themselves in when news broke that a teenager made his way past security to reach the roof’s spire. Mancilla says the New York Police Department called him to demand that the four men surrender last week.

“In our view, they wanted to have control over the media frenzy and how it was going to play out,” Mancilla says.

Brady was still working on 1 WTC as an employee of DCM Erectors when he parachuted from the building on Sept. 30. Mancilla says Brady didn’t use his security ID to reach the roof but instead slipped through a hole in the fence surrounding the construction zone. Mancilla says Brady quit working on the WTC site around Thanksgiving. He says the decision was unrelated to the jump.

The four have been charged with burglary, reckless endangerment and jumping from a structure, which is a misdemeanor in New York City. They’ve been released on bail, and Mancilla says Brady was trying to return to work Tuesday at his job on another construction project.

The recent breaches have raised questions about the site’s security. While the New York Police Department patrols the area around the 16-acre WTC construction zone, the Port Authority of New York and New Jersey is responsible for security on the site. The NYPD referred questions about the site to the Port Authority. Calls and e-mails to the Port Authority went unreturned Tuesday, but the bi-state agency released a statement saying that it “joins the NYPD in condemning this lawless and selfish act that clearly endangered the public.”

Ironworkers may not all be BASE jumpers, but the job does require a certain ability to abandon fear. Not everyone has the nerve to juggle tons of steel while balancing on beams often no more than a foot wide, 100 stories above street level. Like many of his colleagues, Brady was born into the thrill-seeking profession.

“You grow up with it,” Brady said of coming from a family of ironworkers. “As soon as you get around it, you want to do it.”

The adrenaline rush is part of the lure.

“A lot of your ironworkers are guys that were adventurous kids. These are the guys that are skiing 100 miles an hour. These are the guys that are jumping out of airplanes,” Kevin Murphy, the supervisor of 1 WTC’s ironworkers, told TIME for Rise, a Red Border Film that accompanied the WTC story and panorama.

Toward the end of my interview with Brady back in June, along the 102nd floor of 1 WTC, just feet from where he would eventually jump, I asked what was next for him and his fellow ironworkers.

“We really don’t know what we’ll be doing,” Brady told me. “But I don’t know what could top this.”

Contact us at letters@time.com.