Between 2009 and March 2016, authorities searching Boston area waterways recovered the bodies of at least 11 people, mostly young men, who had previously been reported missing, in many cases for days.

It wasn’t the first time tragedy has struck at the water’s edge.

On Sunday , more than two weeks after 23-year-old Michael Kelleher went missing , police pulled his body from the Charles River.

The most recent of those cases was that of 22-year-old Zachary Marr who went missing in February 2016 while celebrating his birthday at a Boston bar. Authorities said they found surveillance camera footage that appeared to show him entering the Charles River nearby. More than four weeks after his disappearance, police pulled his body from the water there.


Divers prepared to search an area. Lane Turner/Globe Staff/Globe Staff

But Boston is not the only place where a series of deaths in similar circumstances have occurred within several months or years.

Since 1997, the bodies of at least 10 young men have been pulled from rivers in and around the relatively small city of La Crosse, a college town along the Mississippi River in Wisconsin, according to news reports.

In numerous other communities, including other Midwest cities like Chicago, Minneapolis, and Milwaukee, there have been clusters of cases of young men turning up dead in the water.

In New Jersey, the bodies of three young men were pulled from the Hudson River between early 2014 and early 2016, news reports said.

In England, 61 bodies, mostly of young men, were recovered from the canals of Greater Manchester between 2008 and 2014, according to media outlets there.

In Boston, as in other places, police have said the vast majority of the deaths were accidents or suicides. Often, drugs or alcohol were involved, according to authorities. In some instances, weather conditions were also bad.


A flyer near the Zakim Bridge asks for information about Michael Kelleher. Lane Turner/Globe Staff

The seemingly high number of cases, coupled with their apparent similarities, has prompted curiosity over the years, and even speculation that the deaths may somehow be connected and the work of a serial killer or killers.

But law enforcement officials working the cases — including the FBI, which weighed in on the Midwest cases — have stressed that they have found no connection between them.

Police in some cities, including Boston, have noted that the number of people rescued after falling or jumping into area waterways was significantly higher than the number of such cases that resulted in death. But the non-fatal cases are typically not well-documented.

Even certain fatal cases may receive less attention than others if, for example, the person hadn’t first been reported as missing.

“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,” Jake Wark, spokesman for the Suffolk district attorney’s office, told the Globe last year.

In some places, officials have searched for solutions, including meeting with bar owners or exploring the idea of building barriers around waterways. But so far, no practical ways to prevent such cases have been found.

“In most cases, it’s nothing suspicious, just an overuse of alcohol,” former Boston police commissioner Edward F. Davis told the Globe a year ago.

Matt Rocheleau can be reached at matthew.rocheleau@globe.com. Follow him on Twitter @mrochele