Rescuers search the Merrimack River for the body of a young man on Wednesday.

A man who went underwater in the Merrimack River in Canterbury on Wednesday afternoon drowned and could not be revived.

Robert Batchelder, 19, of Manchester, had been swimming with a co-worker when he began struggling in the water, according to New Hampshire Marine Patrol. Several bystanders attempted to reach him, but he went under before help could arrive.

At 12:56 p.m., emergency crews responded to a report of a swimmer who had gone underwater in the river near the Hannah Dustin monument and failed to resurface.

While the monument is on the Boscawen side of the river, Batchelder entered the water from Hannah Duston Drive on the Canterbury side.

First responders from the Concord Fire Department launched a boat to search the area and located Batchelder near the middle of the river. They pulled him from the water and immediately began lifesaving measures before transporting him to a local hospital, where he was later pronounced deceased.

Authorities said they don’t believe the death to be suspicious, though the exact circumstances remain under investigation.

Along with New Hampshire Marine Patrol, rescuers from the Canterbury and Boscawen police departments, Merrimack County Sheriff’s Office, Concord Fire Department, Canterbury Fire Rescue Department, and the New Hampshire Fish and Game Department all responded to the scene.

Officials have warned about the dangers of the Merrimack River, where multiple people have drowned over the years, especially when seeking refuge from the summer heat. Although currents look calm from the surface, they can be strong underneath.

Signs placed along the riverbanks in Canterbury included an illustration of a person on the water’s edge and the dangerous drop-off they could experience just feet from the shore.

Gopalakrishnan reports on mental health, casinos and solid waste, as well as the towns of Bow, Hopkinton and Dunbarton. She can be reached at sgopalakrishnan@cmonitor.com