Widower Victor Bates spoke to BBC News outside the Old Bailey after 19-year-old Peter Williams was sentenced to 22 years in prison for the murder of his wife Marian.
Victor Bates says his wife was a victim of policing changes
Williams was one of two men involved in the killing. The second, who fired the shot that killed her, has not been caught.
Mr Bates' views on the sentence:
"There can't be a great deal of consolation but I applaud the judge's verdict very sincerely.
My daughter and I are very lucky to be here. Only through the bravery of my wife are we here this day."
On the fact that Williams had taken off an electronic tag after release from a young offenders' institution:
"I think the people who run these schemes and who are paid by the government for running these schemes ought to be taken to task.
In what way they are culpable I cannot be sure, but I will be conducting my own inquiries to find out."
On the management of Nottinghamshire police:
"I think they used to call it being an accessory before the fact. When you take nearly all the police off the streets and put them into response teams in often remote police stations, the criminals are going to come out to play. And they have.
This is due to experimental police techniques, using the police rather like a fire brigade.
My wife's been a victim of these experimental policing techniques."
On the fact that the gunman is still at large:
"There's still the man who pulled the trigger out there. For the public good and for everybody involved he's got to be brought to justice, wherever he is.
I think the fact that one of the murders has been caught and given a decent sentence should not detract from the fact that the main man is still out there."
Nottinghamshire Police asked for anyone with information about the second man, whom they named as James Brodie, to come forward.