Video footage sheds light on BU professor’s fatal fall at MBTA station, but key details remain unclear

David K. Jones left his Milton home on Sept. 11 for just another afternoon jog.

He headed out with his iPhone, headset, and running glasses in hand, his wife would later tell police. He’d been training for a 50-kilometer run.

Jones likely never considered the possibility he wouldn’t return home.

Not far away, the popular Boston University professor fell to his death through a dilapidated metal staircase outside the JFK/UMass train station in Dorchester — shocking the public and drawing scrutiny of the transit agency and other state officials’ inaction. How the professor had managed to access the staircase — which officials said had been closed off with fencing and signage — appeared to be a mystery.

After authorities released surveillance video earlier this month, the Globe analyzed the footage and photos of the staircase, which provided a fuller picture of what happened to the professor in the moments leading up to his death. Lawyers for Jones’s family have suggested part of the stairs collapsed, causing him to fall.

Passersby going through the busy Red Line stop had noticed deteriorating signs on the structure for years. Officials closed it off with fencing in January 2020 after three stair treads crumbled away. But despite flurries of e-mails and reports between three agencies — the MBTA, the Massachusetts Department of Transportation, and the Department of Conservation and Recreation — none could agree on who was responsible for fixing the rusted-out steps.

Meanwhile, at least one more step fell off the rotting structure. The rickety staircase remained standing, and the sign posted at the top entrance to the stairs — claiming fixes would be complete by fall 2020 — went out of date.

All this was likely unknown to Jones, whose run that September day took him north toward Joe Moakley Park and Carson Beach, under sunny skies with a slight breeze rustling the trees.

As he ran up Old Colony Road, video footage shows he passed a grassy patch outside the JFK station, then slowed to a walk as he crossed nonchalantly under a sign for the station.

Just a few steps away was the metal staircase leading up to the Columbia Road overpass, where cars whizzed by with weekend traffic. Photos after the accident showed a few flat, vertical panels of fencing — slightly taller than an average adult — were propped up in front of the entrance to the stairs. There were no signs, no warnings.

Jones, in the footage, appeared to step past the chain-link barrier at the stairwell’s entrance. He took half a dozen steps up, then glanced down casually as he hit the first landing, turning slightly before pushing forward. He walked casually up the stairs, his back straight. Then he disappeared from the video frame.

Six seconds later, he tumbled about 20 feet to the ground.

The footage and other investigative material released by officials do not show whether he fell through the already missing steps or if more steps fell out beneath him. But lawyers for Jones’s family said another two steps from the structure were recovered amid fresh debris at the scene. They suggested that Jones had noticed the gap and turned to descend the stairs when the treads he was standing on gave way.

“That’s the most likely series of events,” said Darin Colucci, a lawyer representing Jones’s family. “He comes upon where the steps are that are missing, that had been missing there for 20 months, and then in that moment, he stops, goes to turn around, and then the stair collapsed.”

It would be another 15 minutes before a passerby noticed Jones’s body and called 911.

E-mails after the accident showed officials scrambled to answer who had primary responsibility for the structure. A sign later posted at the bottom of the stairs warned “no trespassing.” The following weekend, the staircase was removed entirely.

The Suffolk County district attorney’s office opened an investigation into his death but ultimately concluded last month criminal charges weren’t warranted.

Shortly after his death, Jones’s widow, Sarah Sacuto, called Jones “the most loving, kind, considerate person I knew.”

“The void he leaves behind is unspeakable,” she said in a social media posting.