An off duty Norfolk police officer was canoeing on the Little Ouse at Brandon, Suffolk when he spotted a badly decomposed body partially caught under a tree on one of the banks, Suffolk Police said.
A spokesman said: "Officers immediately attended and the fire service have been alerted for assistance with recovering the body.
"A cordon has been put in place as an investigation gets under way at the scene.
"At this stage, as is standard procedure, the death is being treated as unexplained."
