Police were today attempting to solve the riddle of a dead man discovered entwined in ropes in a river.

Officers want to find out the identity of the bearded man and how he came to be in the River Arun at Fisherman's Quay in Pier Road, Littlehampton.

A passer-by spotted the body in the silt at the side of the river, the second fastest in Britain, at 7.40am yesterday.

Last night it was still not clear how long he had been there and where he had gone into the water.

Police at first feared foul play because the corpse was reported as tied up. But the man, thought to be in his fifties, was just entangled.

He was certified dead at the scene.

Detective Inspector Paul Williams said: "When we got there he wasn't actually floating in the water, but it was low tide.

"He was just out of the water and touching the mud.

"He didn't look like he had been there for more than a couple of days.

"We do not know where or how he went in but we do not believe it was a suspicious death at this stage.

"We are particularly keen to identify the man. We have searched local missing person reports but have not found any matches. Hopefully the post-mortem will shed some light on the matter."

Deputy Littlehampton harbour master David Daniels said: "The river Arun is extremely fast-moving. It can reach speeds of up to six knots.

"The body could have travelled down stream from Amberley or Arundel but that is not very likely. It depends on the length of time the body had been in the water.

"The man could also have gone in near the entrance of the harbour and come in with the tide."

The area where the body was recovered has a lifeboat station nearby and only one other boat is usually moored there.

The dead man had light brown hair and a full beard. He was wearing a brown suede jacket, blue shirt, grey trousers and brown boots.

Police urge anyone who recognises the description or has any information to contact them on 0845 6070999.