A woman who agreed to testify anonymously against gangs of anti-social youths has gone into hiding after her identity was revealed.
The gang surrounded the woman's house after reading court papers
She was to give evidence about drug dealing and vandalism in her street and enable Liverpool City Council to serve Anti-social Behaviour Orders (Asbos).
However court documents revealing her age, sex and street enabled the gang to deduce the 62-year-old's identity.
The council said it was regrettable but she was told of the potential risk.
The woman's home in Chilvers Street, Liverpool, is now boarded-up after the gangs discovered she had compiled evidence of alleged anti-social behaviour - the case has collapsed.
"My mother is on the verge of a breakdown," said her son, Robert Croxton.
"She is absolutely distraught with fear."
He added: "I said: 'Mum, what is it you have done wrong? You have stood up for your community'."
The council wanted to use her evidence to obtain five Asbos but when police served papers the gang saw her age, gender and street on the orders and a gang gathered outside her house.
A council statement said it was "extremely regrettable" the woman's identity had been revealed.
But it said a certain level of detail has to be given to the court in order to prove that alleged incidents had taken place.
The council said it carried an element of risk and it was fully discussed with the family.