Gunman Raoul Moat acted as police informant for years, it was claimed last night.
The killer, who shot innocent PC David Rathband and had vowed to murder other officers, had spent years handing information to police.
And it is believed that his relationship with the police had enabled him to avoid jail despite a string of arrests for violence, including conspiracy to murder.
Despite considering himself 'untouchable' by the law, Moat eventually received an 18-week prison term for assaulting a minor.
It is claimed the sentence sparked his hatred of the force and his 'declared war' on police.
The claim was made yesterday by his former friend Brian Moulding who learnt Moat was feeding information to the law when he gave evidence to help police prosecute him.
Mr Moulding, 29, of Newcastle, told the Mirror: 'I have evidence that proves he was a police informer. I learnt he was an informant because it was referred to in
the legal papers in my case.
'I often wondered why he constantly seemed to escape justice whenever he ended up before the courts and that’s when I realized.
'Given his history and his constantly saying he hated police, you would not believe his past. But it was a front to cover what he was in front of his criminal associates.'
Mr Moulding said in one instance Moat had shown officers where some stolen number plates were hidden.
Moat first became known to the police in 2000 when he was held for conspiracy to murder. He was freed without charge.
In 2005 he was charged over possessing a knuckle-duster and a samurai sword.
Despite admitting having an offensive weapon he walked away with an absolute discharge, a sentence usually reserved for defendants who get a tougher sentence at the same time for another crime.
Moat was also involved in minor scams such as driving away from petrol stations without paying for fuel.
A source who knew of Moat’s history said: 'You would expect a man capable of shooting and killing to have a series of convictions. Moat was detained onmany occasions yet was barely touched by the courts. He had a charmed life.'
Another source close t
o the case said: 'He was arrogant whenever court officials dealt with him. He thought he was above the law.'
Northumbria Police paid informants nearly £192,000 in 2008-09, the seventh highest in the country.
A source said: 'We know Moat had a grudge against us. The assumption was that he hated us because he was locked up. We could not comment on our use of informers.'
Last night a former girlfriend of Moat and the mother of two of his children, Marissa Reid, 37, told how he had made her life hell with a string of beatings, a vicious rape and mental torture during jealous rages fuelled by a cocktail of steroid drugs.
Miss Reid, who had a nine-year-relationship with Moat, told the Mirror: 'I always thought that he would kill me and just hearing his voice would make me shiver. That man was a living, breathing monster. Thank God he's dead. He made mine and my children live a misery, I can never forgive him for that.