Alistair Wilson was gunned down on the doorstep of his home

Mr Wilson, 30, was shot dead on the doorstep of his home in Nairn near Inverness last November.

Detectives revealed that the CCTV camera on the wall of Nairn's Free Church failed to record properly on the night of the murder.

The company which provides the system has agreed to change the recording software used at 12 camera sites.

Councillor Drew McFarlane-Slack, head of Highland Council's CCTV working group, said: "We obviously have some concern over the recording equipment and the security company are in the process of replacing parts of it.

Finding clues

"They are dealing with the supplier to make sure our equipment is in good order and establish what caused the problem."

A Northern Constabulary spokesman said it was their understanding that the recording software was to be upgraded.

He added that while the camera that was not working on the night of Mr Wilson's death had been replaced, the remaining CCTV cameras in the Nairn area would not be changed.

It is three months since Mrs Wilson opened the door to the killer of her 30-year-old husband.

The police admitted during a news conference on Friday that despite extensive publicity, DNA testing and the case being featured on the BBC's Crimewatch programme, they were still no nearer solving the case.

They have been looking into Mr Wilson's business and personal life in the hope of finding clues.