AN investigation has been launched after a woman claims she warned police about two killers only four weeks before they set fire to a house in which an 11-year-old boy died.

Dean Pike, of Mordey Close, Sunderland, died when Terry Majinusz and Neil English burned down his house as he slept. They were jailed for life last week.

But now Lisa Waterworth, a former girlfriend of Majinusz, said that she warned officers after the pair threatened to firebomb her house only weeks before they killed Dean.

Detective Superintendent Barbara Franklin, who led the murder hunt, has called in the Northumbria Police professional standards department to investigate Miss Waterworth's claims.

Miss Waterworth, from Grindon in Northumberland, said officers did not even log the complaint or give her a crime number.

She said: "If the police had spoken to them about threatening me it might have scared them off and maybe they wouldn't have done what they did to Dean's house."

Miss Waterworth had been seeing Majinusz for six months and in May last year told him she wanted to split up.

But despite having another teenage girlfriend, Miss Waterworth claims Majinusz "went mad" and told her he would kill her little sister Christine, 11, and her parents Fiona, 45, and David, 50.

Only a month later the pair - targeting the family of Majinusz's other girlfriend Ashley Lawson - wrongly set fire to Dean's home.

The pair poured lighter fuel through the letter box while Dean and his mother, Janine Dodd, slept upstairs. While she escaped, Dean died in the blaze.

Majinusz and English, both from Sunderland, were found guilty of Dean's death and guilty of causing grievous bodily harm with intent to his mother at Newcastle Crown Court last week.

A Northumbria Police spokeswoman said: "The senior detective who has investigated Dean Pike's murder has passed details of this previous report to our professional standards department, which is carrying out a full investigation into the circumstances and actions of the officer involved."