What we know

It is not clear how many people carried out this attack, but one of the offenders did injure themselves, leaving blood at the scene.  Forensic analysis has given detectives a full male DNA profile.  This has been run through the national DNA database in the UK which has not provided a match. Similar database searches have been done around the world and to date there have been no matches.

Detectives also found suspect footprints at the scene that match Converse trainers. With the help of Converse in the USA the print type has been narrowed down to a particular upper, which is available in two styles and was largely sold in Europe and North America at the time.

It was established during the early stages of the investigation that Alan's bank cards had been used in Bourne and Stamford over a couple of days after his murder at ATM cash points. A trawl of thousands of hours of CCTV revealed images of a person who can be seen below.

The person appears to be 5ft 9in to 5ft 11in tall , dressed in a "smart casual" manner and from the CCTV images they  appear to be wearing a distinctive striped scarf.  The person has an unusual walk and experts outside of the force have analysed CCTV footage and come to the conclusion that that he limps due to his right leg being slightly longer than his left leg. The offender may also have been injured after the crime as blood was found at the scene. That injury could be to their hand.

A witness at one of the cash machines has also helped the police create this picture of the suspect