A mum who tirelessly campaigned against violence after her son and his babysitter were murdered has died at the age of 40.

Tributes were today pouring in for Denise Copley, who collapsed and died of a heart attack during a holiday in Hornsea.

Mrs Copley became a trustee and active member of the national campaign group Mothers Against Murder And Aggression after son Jonathan, seven, was murdered along with 15-year-old Rachel Rooney.

Her family believe the continued grief and stress of coping with her son's murder affected her health. Mrs Copley and one of her daughters, Liz, then 15, who was a close friend of Rachel, made the shocking discovery when they returned to their home in Little Horton, Bradford, in February 1995.

Jonathan and Rachel had been murdered by Tariq Rehman, then aged 35, who lived with Rachel's mother Christina in Queensbury. They had been repeatedly stabbed with scissors.

Last year, Mrs Copley took part in a sponsored walk from Dunblane to London to draw attention to their organisation.

Her daughters Liz, now 20, and Louise, 23, said they remembered their mum as "lovely, lively and loud."

They said the family, including Mrs Copley's sister, Yvonne Sugden, were taking comfort from the fact that Jonathan has been reunited with his mum. Today is also the first anniversary of the death of Mrs Copley's father. Louise said: "That's how we are coping. We know they're all together. It makes it a bit easier. She's not on her own. She had suffered enough."

Liz, of Horton Bank Top, who has children Amy, three, and eight-month-old Abby, said her mother's work for the anti-violence group had been vital for her. "It kept her going. It was very important to her."

Louise, who has a one-year-old son Jack, said: "It was something good that came out of something bad."

Mrs Copley had been in Hornsea with her partner Terry Keating, who is said to be devastated at her sudden death last Friday.

She had been suffering some pain recently but the heart attack had been unexpected. They said Mrs Copley would be greatly missed by many people, including her close friends Diane Smith and Sharon Wood. Mrs Smith said: "Denise put everybody else before herself." She added: "Jonathan has got his mum back."

Last February, the fifth anniversary of Jonathan's death, Mrs Copley, who lived in Wibsey, spoke exclusively to the T&A about his death and her life since.

She described the murder scene in her home as being "total horror". She said the memory would never leave her.

She also told how she broke down after giving evidence at Rehman's trial. He was convicted of both murders and sentenced to life in 1996. She said her son's murder had left a huge hole in her life. "He loved cuddles. He was such a cuddly kid," she said. "I speak to his photograph a lot and I've got his picture on my keyring."

She added: "There can be a record playing, or a photograph, and my little grandchild aged two sometimes resembles him when she looks at me. Jonathan would have been 12 now. I've got a nephew aged ten, so I look at him and see what he's doing at different ages. You carry on, but it never leaves you."

Dee Warner said she and fellow founder members of MAMAA, Lyn and Roger Costello, were devastated at her death.

"We loved her to bits. She did so much for us. Denise first contacted us when she saw us on TV and she raised a lot of money. She got all her family and friends involved. After all she had been through, she still had so much compassion for other people."

All three co-founders of MAMAA will be at her funeral tomorrow at Queensbury Parish Church at 2.30pm. A collection for MAMAA will be made.