Police are seeking information after a man's body was found in a river.
A pair of young canoeists called Hertfordshire Police after finding the body in the River Stort in Bishop's Stortford at about 11:45 GMT on 23 March.
Officers have been unable to identify the man, who was in his 20s.
"This is a very sad case because we still do not know who this man is, or what his story was," said Det Sgt Thomas Nash.
"We believe his body may have been in the undergrowth for a considerable period of time and our main priority is to trace this man's family so they can lay him to rest."
The death is being treated as non-suspicious but unexplained.
Police described the man as being of medium build, with facial hair and about 5ft 10in (1.78m) tall.
He was wearing a black Adidas hoodie, dark grey Nike Air tracksuit bottoms and black Adidas trainers.
Anyone with information has been urged to contact Hertfordshire Police.
