The mother of a teenager murdered by a convicted rapist has said she will sue four police forces for failing to keep track of the man who killed her.
Facebook killer Peter Chapman was allowed to slip away from Merseyside Police with "terrible consequences", the Independent Police Complaints Commission (IPCC) said this week.
It blamed "inadequate resources" for the "poor management" of the predator who murdered 17-year-old Ashleigh Hall in October 2009 after he pretended to be a teenager when he befriended her on Facebook.
The IPCC report revealed Merseyside's Knowsley sex offender unit - tasked with monitoring Chapman - was being run by a single female police constable who was in charge of monitoring more than 60 sex offenders and was making visits alone in her own car due to a lack of resources.
Andrea Hall, 41, from Darlington, said she was going to sue the Merseyside, Cleveland, Durham and North Yorkshire forces for failing to keep track of the 32-year-old killer.
She said: "It's not about money, I have got to prove a point.
"They were in the wrong and if they had done their job properly my daughter would still be here.
"I wouldn't like to think of this happening to anybody else."
When the IPCC report was published on Wednesday, Assistant Chief Constable Andy Ward, of Merseyside Police, said the force had put in place "a number of improvements" to strengthen the management of sex offenders.
He added: "However, it is clear that, in this case, the process we had in place at that time fell short of the required standard."