Fugitive Raoul Moat vowed not to stop killing "till I'm dead" as he declared "war" on the police in a letter passed to a newspaper.
The 37-year-old former nightclub bouncer blamed Northumbria Police for ruining his life in the 49-page handwritten confession sent to the force and published in The Sun.
Headed "Raoul Moat Murder Statement 4/7/10", the document - written in capital letters and handed to a friend in Newcastle - warned that police would "pay for what they've done" to him and his ex-girlfriend, Samantha Stobbart.
He wrote: "The public need not fear me but the police should as I won't stop till I'm dead."
He described himself as a "killer and a maniac but I ain't no coward", and went on: "I guess I've finally lost it.
"I'm not on the run, I will keep killing police until I am dead. They've hunted me for years, now it's my turn.
"I am very sorry about Sam and wish I hadn't shot at her.
"Just make sure she stays alive."
The frantic hunt for Moat entered its fourth day as officers faced a probe into their handling of the case.
Moat, from the Fenham area of Newcastle, allegedly went on the rampage after being released from Durham Prison on Thursday.
It emerged yesterday that police were warned he may have been planning to harm his ex-girlfriend on Friday, the day before he allegedly shot Miss Stobbart, 22, and killed her new boyfriend, Chris Brown.
The next day the fugitive also allegedly shot and injured Pc David Rathband.
Admitting his actions, Moat claimed he was "pushed", saying he "went straight but they couldn't let it go", and apologised for hurting Miss Stobbart, with whom he has a daughter.
"Last night I called 999 and declared war on Northumbria Police before shooting an officer on the West End A69 roundabout in his T5," he wrote.
"Sitting there waiting to bully someone."
Northumbria Police said they had referred the case to the Independent Police Complaints Commission (IPCC).
Last night, officers also issued details of a car connected to the suspect which officers are trying to trace.
The vehicle is a black Lexus with the registration number V322 HKX.
It is described as being very noisy, with a full body kit, two regular alloy wheels and two "space saver" thin wheels. It also had damage under its bumper at the front nearside.
Superintendent Dennis Shotton said: "We have information that this car is connected to Moat, although it does not belong to him but to an associate. We are keen to trace it as it may help us to locate Moat."
Tensions remained high in Newcastle yesterday, where people were arrested and released by armed police in at least two incidents.
Northumbria Police Temporary Chief Constable Sue Sim revealed that a warning about the fugitive came from Durham Prison on Friday.
Moat had been jailed for 18 weeks for assault and was released on Thursday.
"Northumbria Police were not informed that Mr Moat intended to shoot or kill Samantha Stobbart," she said.
"We were informed on Friday afternoon by Durham Prison that Mr Moat may intend to cause serious harm to his partner.
"We acknowledge that it is important that these matters are investigated thoroughly, and I have voluntarily referred this aspect to the Independent Police Complaints Commission, and we will of course fully co-operate with the Independent Police Complaints Commission."
At a press conference, police said Miss Stobbart - who is being "appropriately protected" - was no longer in a critical condition and was "improving".
She issued a direct appeal to Moat, through the police, saying: "Please give yourself up. If you still love me and our baby you would not be doing this."
Detective Chief Superintendent Neil Adamson urged Moat: "I want you to realise you do have a future. We can only help you with this if you make contact with us directly."
Moat mistakenly believed Miss Stobbart was having an affair with a police officer.
He is understood to have fired at Miss Stobbart - with whom he had a six-year on-off relationship - through the living room window of a house in the Scafell area of Gateshead.
Moments later, Mr Brown, 29, is believed to have left the property - only to be struck down around 50 metres from the front door.
Less than 24 hours after the attack, a man identified as Moat was linked to a shooting in East Denton, Newcastle.
Pc Rathband, 42, a married father of two with 10 years' experience on the force, was shot in the face and chest through the passenger window of his car in an "unprovoked" attack while on duty. He had been parked on a roundabout.
The officer underwent surgery on Sunday night and his condition remains critical but stable.
The suspect is described as 6ft 3in, white, of large, muscular build and with very short or shaven blond hair and blue eyes.
Members of the public were warned not to approach him.
Today police launched an operation at an address in the Springwell Road area of Gateshead.
A force spokesman would only say that it was an "on-going operation".
Dozens of extra armed officers have been drafted in to help in the manhunt.
Yesterday a number of people were arrested at gunpoint but were later released as police followed up reports of sightings of people resembling Moat.
People living in Springwell Road said a police helicopter hovered over the area from about 6.45am to 8.30am.
One local resident, who asked not to be named, said she had not seen any police officers but noted that traffic was much heavier than usual.