WALTHAM (CBS) – A 20-year-old Waltham man died while swimming in a reservoir Wednesday evening.

State Police said the victim was swimming in the Stony Brook Basin with two friends when he went missing at about 5:30 p.m. Fire officials say they were swimming near some cliffs at the time. The victim’s friend alerted police.

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Divers recovered a man's body from the Stony Brook Basin (WBZ-TV)

Divers recovered a man’s body from the Stony Brook Basin (WBZ-TV)

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The victim’s body was recovered approximately two hours later by divers from the State Police and regional dive team. His name has not been released.

The reservoir on the Waltham/Weston line provides drinking water to the city of Cambridge. Its caretaker says the water is 32 feet at its deepest, and says he is constantly cutting down ropes and kicking out swimmers.

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The Middlesex District Attorney’s Office is investigating the drowning.