"The video shows a male heading toward the water and disappearing," said Boston Police Commissioner William Evans. "We believe that is him. It's a sad case."

The recently discovered footage prompted a renewed search for Marr's body Tuesday, as Boston and State Police dive teams scoured the water near the Charles River Dam. Marr, who was visiting Boston from the town of Harvard, was last seen outside the Bell in Hand Tavern near Faneuil Hall around 1:50 a.m. on Feb. 13.

The family of Zachary Marr, a 22-year-old who went missing Feb. 13, said they are holding out hope for his safe return, despite the emergence of video footage that police said appears to show Marr disappearing into the Charles River under the Zakim Bridge.


Matthew Marr, Zachary's father, said police recently contacted the family about the grim footage, which shows Marr on a walkway, and then walking on train tracks before he disappears into the water.

Marr said he recognized that the video appears to confirm the worst fears about Zachary's fate. But for now, he refuses to believe that his son is dead.

"Nothing is final, until it's final," Marr said. "The percentages have been getting thinner. And it's thin now. But there's always that 1 percent that you hold on to."

Marr said he suspected that Zachary might have tried to swim in the river, or fell through the walkway.

"I just want him home. I just want to get closure," Marr said. "I know that he probably won't get home . . . but our floodlights will stay on anyway."

Since 2009, at least nine bodies, mostly of young men, have been found in the water in the Boston area. They generally involved drugs or alcohol, while some were accidental drownings or suicides, law enforcement officials said.

Officials have grappled with how to prevent those incidents.


"When you see something like this happen, it's a tragedy and you want to do everything to stop it," said former Boston police commissioner Ed Davis.

During his tenure, the department was unable to find "a viable solution" to prevent the accidental deaths, many of which were caused by a combination of alcohol and poor weather conditions, Davis said.

"In most cases it's nothing suspicious, just an overuse of alcohol," he said.

Davis said discussions were held with bar owners about the problem, but no solution was reached.

The nature of the incidents, and the diversity of the cases, complicated the search for the solution, Davis said.

Marr's disappearance appears similar to that of 24-year-old Eric Munsell, who vanished in February 2014 after he was kicked out of the Market bar and lounge in the Financial District. A bouncer allegedly saw an intoxicated Munsell bumping into customers.

After leaving the bar, Munsell stumbled up the block. Two months later, his body was pulled from the harbor near Long Wharf. Investigators said they did not suspect foul play.

On New Year's Eve 2015, after a monthlong search, the body of Northeastern University student Dennis Njoroge, 21 was found in the Charles River. His death was not believed to be suspicious.

In 2012, at least four people were recovered from Boston's waters, including Franco Garcia, a Boston College student who disappeared on his way home from a Brighton bar. A preliminary autopsy suggested that Garcia died from an accidental drowning.


Four months later, Treshawna Williams, a 20-year-old mother, was found in the water at Constitution Beach. Investigators said her death was not the result of foul play.

Over two days in October that year, police discovered the bodies of 69-year-old Pedro C. Rodriguez and missing graduate student Jonathan Dailey, 23, in the Charles River.

"Many of these cases are clearly accidental, others are clearly suicides, and in some the evidence doesn't point conclusively in one direction or another, but there are no signs of trauma or other indications of foul play," said Jake Wark, spokesman for the Suffolk District Attorney's Office.

"A relatively minuscule number, over the years, have been homicides," said State Police spokesman David Procopio. "If there is any evidence to suggest a crime has been committed, we act accordingly. But that is usually not the case."

In a recent five-year period, more than a dozen people who had fallen or jumped into water near the Tobin Bridge were saved thanks to passersby who witnessed the incidents and alerted authorities, Wark said.

John R. Ellement of the Globe staff contributed to this report. Astead W. Herndon can be reached at astead.herndon@globe.com. Follow him on Twitter @AsteadWH