The family and friends of a 70-year-old man feared murdered while selling his £120,000 boat said today they believe he is dead.

Meanwhile police released without charge a 44-year-old Bognor man they had been questioning over Robert Saint's disappearance.

A close friend of retired businessman Mr Saint, whose boat was found covered in blood, said the family now accepted they were looking for a body.

Mr Saint, who worked in the timber industry, travelled from his home in Horsham Road Steyning, to meet a man at Birdham Pool, near Chichester, to sell his 42ft motor cruiser for cash.

The prospective buyer of the boat had tried to buy the boat with a cheque but it bounced, Sussex Police said today.

Witnesses claim to have seen the boat, called Sundowner, leaving Birdham at lunchtime on Thursday. It is not known whether Mr Saint was on board, The vessel was seen passing East Head, near Wittering, and was spotted as far away as Portsmouth before being found moored at Itchenor.

There was no trace of Mr Saint. Blood was found in the galley.

Tests were still being carried out to ascertain whether the blood was Mr Saint's.

Today family friend Cynthia Foulkes, 60, spoke on behalf of Mr Saint's relatives, including his son Glenville, 49, who appeared at a news conference but declined to answer questions.

She said: "Over the past few days we have had to come to terms with the sad reality that we are probably looking for a body. We know that if Bob was alive he would have made contact long before now.

"We have to know what happened to him and where he is now. I would urge anyone with any information regarding that last journey on Sundowner to contact the police urgently."

Det Chief Insp Tony O'Donnell, leading the investigation, said he was sure Mr Saint had been murdered.

He said it was "suspicious" that the buyer of the boat had promised to pay in cash and added that Mr Saint had been taken advantage of.

Mr O'Donnell said there was no reason to suspect suicide and that no weapon had been found on the boat.

He added: "No weapon has been recovered. I would also say that due to the fact that a significant amount of blood was found on the boat, it would tend to suggest that something happened there."