Police investigating the “brutal and savage” murder of James Attfield have hailed the impact of a recent BBC Crimewatch appeal - but are still urging 11 potentially crucial witnesses to come forward.

Mr Attfield, 33, was found seriously injured with more than 100 stab wounds in Castle Park off Guildford Road, Colchester, shortly before 6am on Saturday, March 29. He died a short time later at the scene.

A number of people caught on CCTV in the park have got in touch with police following the Crimewatch appeal to discount themselves from he investigation.

However, detectives are yet to hear from eight separate men, one woman, and the man and woman who sat on a park bench opposite where Mr Attfield could have been sitting on the grass.

The man and woman were there at 11.30pm on Friday, March 28, and were sitting at opposite ends of the bench. Police are unsure whether they were there together or not.

The man is white, of stocky build and has long legs, while the woman is white.

Approximately 10 metres away, a man was sat on the grass who was white, aged in his 30s and wearing a dark jacket and possibly jeans. Police believe this may be Mr Attfield.

Senior investigating officer, DCI Simon Werrett, said: “Crimewatch was a success as it registered with people and got them to contact us so that they could be eliminated from our enquiries.

“This frees up more capacity for us to scrutinise everything and anything again for clues as to why James was attacked and who is responsible for his murder. We still need people to contact us with vital information.”

A man and a woman, both aged 27 and from Colchester, are currently on police bail until Friday, May 9, having been arrested in connection with the murder.

Police are still trying to trace Mr Attfield’s movements from when he left the River Lodge pub at 10pm on Friday until he was found.

A Crimestoppers reward of up to £5,000 still remains on offer for information which leads to the arrest and conviction of those responsible.

Anyone with information is asked to call Essex Police on 101 or Crimestoppers anonymously on 0800 555111.