Pictures of martial arts enthusiast Ann Sanderson were released by grieving friends yesterday as details emerged of her tortured psychiatric history.

Miss Sanderson, 37, had a record of mental illness and an obsession with lighting fires which made her a familiar face to local police.

The unmarried factory worker was killed in Sevenoaks, Kent, in the early hours of Monday after waving a ball-bearing gun at officers.

One theory is that she goaded the armed response unit into firing at her in a bid to commit “suicide by cop”.

Yesterday, as the Independent Police Complaints Commission continued its inquiry into her death, friends told how her mental condition deteriorated after the age of 12 when her mother Mary died of cancer.

Former classmate Steven Scutchings, 37, described her as a “loner” but added “she had a heart of gold”. Another ex-classmate said: “She was a good person. I just think she lost the plot.” For the last few years she had worked at a guitar string factory in Sevenoaks where colleagues described her as “irreplaceable”.

Ms Sanderson was also praised by neighbours in her street, less than a mile from where she was killed. Vivian Bain, 43, said: “She was a lovely neighbour. She was always helping me out with little problems.”