Police were warned by prison staff that suspected gunman Raoul Moat may have been planning to harm his ex-girlfriend the day before he allegedly shot her and killed her new boyfriend.
As the hunt for the fugitive continued, Northumbria Police temporary Chief Constable Sue Sim said the warning came from Durham Prison on Friday. The case has been referred to the police watchdog.
Moat, from the Fenham area of Newcastle, was released from prison on Thursday after being jailed for 18 weeks for assault.
On Saturday Moat, 37, allegedly shot Samantha Stobbart, killed her boyfriend Chris Brown and fled. The next day the former nightclub bouncer allegedly shot and injured Pc David Rathband.
At a press conference, police said Miss Stobbart, 22, 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 revealed police had received a hand-written 40-page letter in the last 24 hours purportedly from Moat and urged him: "I want you to realise you do have a future. We can only help you with this if you make contact with us directly."
The detective said there were indications that other people may be at risk and a number of them had been given police protection. Miss Stobbart was being "appropriately protected", he added.
Tensions remained high in Newcastle, where people were arrested and released by armed police in at least two incidents.
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. Ms Sim said Pc Rathband underwent surgery on Sunday night and his condition remained critical but stable.