Sion and Lois Jenkins also disclosed that their 10-year-old daughter was the first to discover the body of Billie-Jo, 13, who was bludgeoned to death on Saturday while painting a patio door at her home in Hastings, East Sussex.
Meanwhile, police yesterday released into the care of a local health trust a 44-year-old local man who they had been questioning about the murder. Police are also investigating reports from Billie-Jo's schoolfriends that she feared she was being followed by a man shortly before her death.
At a press conference yesterday the couple, who became Billie-Jo's legal guardians after fostering her for four years, said they had been plagued with prowlers and nuisance calls and had felt a "sense of unease" since January.
Neighbours had reported to the police a person standing on the Jenkins' window ledge looking into their home; also the house next door was burgled, and men were seen loitering in the nearby park.
Mr Jenkins, a deputy headmaster, said they had moved from east London to give their children a better quality of life.
He said: "We moved to the house because of the park and because of the children. But January has been a very strange and uneasy month. As a family, we have felt uneasy about prowlers.
"On one occasion I was looking out of the back window and I thought I saw movement. I switched on the outside security light and got a fleeting glimpse of somebody moving about. Another time I saw somebody in the park staring at the house.
"The problem is we live directly opposite the park entrance and there are always a lot of people coming and going. But we had decided to put the house on the market and were looking at a house in the old area of Hastings."
Mrs Jenkins, a social services project manager, said: "We had decided to move house because of the problems in the area." The Jenkins did not contact the police about the recent prowlers and telephone calls.
Mr Jenkins said his daughter Lottie, 10, was the first to discover Billie- Jo's body when she, her father and her 12-year-old sister, Annie, returned from a music lesson 40 minutes after leaving their foster sister painting the patio doors. She had been beaten over the head several times with an 18-inch metal tent spike.
Mr Jenkins said: "Annie and Lottie are clearly very upset. Lottie was the first person to see Billie-Jo when we returned and for that day and the day after she was totally distraught."
He said that his younger daughters Myra, seven, and Esther, nine, had not really taken in what had gone on.
Both foster parents have spoken to Billie-Jo's natural mother Debbie Wood and her father William Jenkins, who are being counselled by police in London.Reuse content