Veronica Wilson has been trying to cope with her husband's death

Father-of-two Alistair Wilson, 30, was gunned down by a lone killer at his home in Nairn at the end of November.

Veronica Wilson, 33, said her husband had not been acting strangely and was not concerned when someone called at the door.

She has made a personal appeal to the public to help the police.

In an interview with the BBC, Mrs Wilson said she has been trying to think of why someone would kill her husband.

She said: "I've searched and searched from the minute it happened and that's what I think makes it so much harder.

"There is still nothing at all. I almost feel it would help if I did, if I had known he had been involved in something, but there was nothing at all."

In my mind, he could not have known about it because if he felt danger he would have shared it with us or protected us Veronica Wilson Victim's widow BBC interview

She added: "What reason is there to kill someone like that anyway?"

"You are thinking: Did he fall out with someone at the supermarket? Did he pull out in front of someone with the car? But would you kill someone because of that?"

Mrs Wilson said that her husband had shown no concern when a man turned up at the front door at 1915 GMT on Sunday, 28 November.

She said he "just went away and answered the door as though it was two in the afternoon and it was a friend calling".

She believes that mistaken identity was the "only reason which makes sense".

"I just can't think what my husband had said or done to anyone that deserved this," she said.

Mrs Wilson said her husband did not appear to be troubled

"In my mind, he could not have known about it because if he felt danger he would have shared it with us or protected us.

"He was a family man and he would have shared it for our protection. He would not have let anything happen to us."

Mrs Wilson said that the daily routine of life with her young sons has helped her to carry on after her husband's death.

"He's gone and that's hard enough to deal with but to not know why he's gone just makes it more unbearable," she said.

She dismissed suggestions that she had played a part in her husband's death.

"Why would I? I don't see what they think I had to gain," she said.

"To come down and see my husband like that... No. People may think that but they don't know anything about us.

"To do this to my children as well, for the rest of their lives. Their dad will always have been murdered. This was on my doorstep, my home."