Anthony Grainger was 36 when he was shot dead in a Cheshire car park in March 2012 by a Greater Manchester Police officer known only as Q9.
No weapons were found in the red Audi he had been sitting in when he was shot.
Mr Grainger's family have acknowledged his criminal record and that he knew some of Greater Manchester's most serious offenders. But they insist that becoming a father had steered him away from trouble.
Mr Grainger left behind a daughter, 10, and a four-year-old son.
His mother Marina Schofield has vowed that her seven-year battle for justice will continue regardless of the findings of the public inquiry into her son's death, which are due to be published today in Liverpool.
She told Sky News that the police failings examined in the inquiry have left her with an unshakeable opinion: "Q9 murdered my son, there is no other way of saying it. I have said it in court, I don't care.
"I want them held to account," she added. "It has got to end somewhere... they can't keep saying there are lessons learned because there are no lessons learned."
Q9 was one of 16 police officers deployed to the car park opposite a small shopping centre in the village of Culcheth near Warrington on the evening of Saturday, 3 March 2012.
It was the culmination of a six-month police surveillance operation that had focused primarily on another man in the car called David Totton.
The police suspected that Totton, Mr Grainger, and a third man were planning to carry out an armed robbery in the village.
As the officers surrounded the vehicle Q9 said that he saw Anthony Grainger drop his arm as if he was reaching for a weapon inside the Audi.
Q9 told the inquiry "It was a deliberate movement, as if he was grabbing a firearm."
The officer felt the movement coupled with the information he'd been given before the operation, that there may be a weapon in the car, gave him "clear justification" for opening fire.
Another officer, known as X7, gave a different account - he said he was next to Anthony Grainger at the Audi driver's window.
He shouted "armed police show me your hands" - Anthony Grainger raised both his hands, X7 said.
Mrs Schofield believes it helps explain the shooting - while Q9 said there was not another officer "covering" Anthony Grainger when he shot him, X7's evidence suggests he was much closer to the suspect: "Anthony was actually looking at him (X7) with his hands up and the next thing he (X7) heard a crack he didn't know where it had come from and Anthony lowered one of his arms.
"It is obvious to me he has shot him while other police officers are there at the side of him."
GMP have conceded in court that errors were made in the operation's intelligence gathering and sharing. The force also acknowledged officers should not have used a CS gas canister because they did not have the correct permission.
During the hearings it also emerged that the Met police officer who shot dead Mark Duggan in Tottenham, north London, the previous summer - a death that prompted widespread rioting and looting - travelled north to meet Q9 five days after the Anthony Grainger shooting.
The officers met before Q9 had provided detailed interviews to the team of independent police investigators.
Marina Schofield's solicitor, Jonathan Bridge, told Sky News it was indicative of a police culture that cannot be allowed to continue: "There can't be any justification, to get good evidence you have got to interview the shooter straight away without any collusion with any other officers and that didn't happen."
A spokesman for GMP has confirmed they will respond to the findings of the Grainger Inquiry once the final report is published later today.