Joan and John Stirland were gunned down in a revenge attack led by Nottingham crime boss Colin Gunn.
An inquest jury has now ruled Nottinghamshire Police's failure to share intelligence contributed to the couple's killing by the criminal gang.
Here is a timeline of events surrounding the killings.
Marvyn Bradshaw is shot dead outside the Sporting Chance pub in Top Valley, Nottingham.
He was in a car with a group of friends, which included Colin Gunn's nephew Jamie Gunn.
Shots are fired at the Stirlands' home at Carlton in Nottingham. It happened days after Mrs Stirland's son was arrested for the murder of Marvyn Bradshaw.
A statement issued by Mrs Stirland after the incident said: "It is only by luck that myself or John were not seriously injured or killed.
"We now fear for our own personal safety."
The couple decide to move and eventually settle at a "safe house" in the Lincolnshire village of Trusthorpe.
Joan Stirland's son Michael O'Brien is jailed for life for the murder of Marvyn Bradshaw at Nottingham Crown Court.
During the trial, the court was told Mr Bradshaw had probably been mistaken for another person involved in an earlier argument with O'Brien on the night of the shooting.
2 August 2004
Jamie Gunn dies from pneumonia after suffering from depression.
His family said his health had deteriorated since the shooting of Marvyn Bradshaw and he died from a "broken heart".
8 August 2004
Michael O'Brien's mother Joan Stirland and her husband John are murdered in a revenge attack at home in Trusthorpe.
Mrs Stirland had called police after a neighbour saw a prowler. She died shortly after speaking to an officer but it was several hours before police arrived at their home and found the bodies.
30 June 2006
Colin Gunn is jailed for life for conspiring to murder the couple at Nottingham Crown Court.
Co-defendants John Russell, 29, and Michael McNee, 22, are jailed for 30 and 25 years respectively.
1 July 2006
Following his sentencing, Gunn's supporters riot in Bestwood, Nottingham.
Cars are set on fire and up to 30 people go on the rampage after Gunn and his accomplices are jailed.
26 October 2006
Former trainee detective Charles Fletcher is jailed for corruption.
Fletcher had passed on police data to Gunn and ran searches about the Stirlands' address in Nottingham shortly before shots were fired at it in September 2003.
4 November 2006
Several people are jailed for their part in the riot at Bestwood.
The ringleader Matthew New, 23, from Bestwood, is jailed for three-and-a-half years after pleading guilty to violent disorder.
O'Brien's friend Gary Salmon is jailed for life for his part in Marvyn Bradshaw's murder.
The court hears how he had produced a gun and loaded it on the night.
Colin Gunn is convicted of engaging in police corruption.
He is found guilty on two counts of conspiracy to cause misconduct in public office after using a corrupt detective to get information on police inquiries into his network.
An Independent Police Complaints Commission (IPCC) report finds that the Nottinghamshire force's sharing of intelligence with Lincolnshire Police was "unacceptable" over the Stirlands' murders.
The report says Lincolnshire Police were given only the barest of details about who Mr and Mrs Stirland were and communication between the two forces was not as good as it could have been.
An inquest jury at Lincoln Crown Court finds the couple were unlawfully killed and that failures by Nottinghamshire Police contributed to their deaths.