A Boston University professor died over the weekend when he fell about 20 feet through a rusted-out staircase near a train station, according to university and law enforcement officials.

David K. Jones, an associate professor in the university’s School of Public Health, died Saturday, according to a statement posted Sunday by the school’s dean, Dr. Sandro Galea.

“In truth I have no words to describe the devastation of this news,” Galea wrote. “David joined the School of Public Health in 2014. He has, since then, been an exemplary member of our community.”

The death of Jones, 40, of Milton, is under investigation by state police, according to a statement Monday from agency spokesperson David Procopio.

Troopers responded to the area near the JFK MBTA station in Boston at about 1:30 p.m. Saturday after a passer-by spotted Jones’ body, he said.

“Investigation revealed that Mr. Jones was laying on the ground under a stairway,” the statement said.

Troopers “observed a gap in the stairs above the victim, who had already been determined to be deceased. Preliminary investigation revealed that the stairs had been deemed unsafe and closed for approximately 20 months,” he said.

Both the top and bottom of the stairs had been blocked off, he said.

Jones’ wife in a social media post said he had gone out for a run and fell about 20 feet.

“He was the most loving, kind, considerate person I knew,” Sarah Sacuto wrote. “He was the best father. He loved to dance to Phish, be outdoors, and run. He loved unconditionally and was the proudest father to his kids. I loved him.”

Jones had an undergraduate degree from McGill University in Montreal, Canada, and advanced degrees from the University of North Carolina and the University of Michigan, according to his university profile.

He is originally from New York City where he once worked as a pretzel vendor at Yankee Stadium, according to the university.

He was founding editor-in-chief of the Public Health Post, an online forum for public health policy launched in November 2016; was awarded an Association of University Programs in Health Administration prize for young investigators; AcademyHealth’s Outstanding Dissertation Award; and the BU School of Public Health Excellence in Teaching Award.