A nine-year-old West Midlands girl who was believed strangled by her mother's boyfriend and then dumped in the cab of his lorry was today named as Stacey Lawrence.

The man, who was found hanged nearby, was 40-year-old Darren Walker, Northamptonshire Police said.

The pair had left a lorry depot in Willenhall on Friday morning before making deliveries to Norfolk and Peterborough. The owners of the lorry tracked the vehicle down using GPS when Mr Walker failed to return with the Spar truck on Friday evening.

Detectives are today investigating whether  Stacey had been sexually abused prior to her death.

Her body was discovered on Saturday afternoon in the back of the man's lorry, which was parked at a Little Chef on the A605 near Warmington, Northamptonshire.

The lorry was operated by A F Blakemore based in Willenhall.

Mr Walker's body was found hanged from a tree in nearby woodland, Northamptonshire Police said.

Stacey, who along with the man is from the West Midlands, regarded the trip as a "treat", and her mother had no concerns before her tragic death, Det Ch Insp Tricia Kirk said.

She went on: "Any death is distressing for police officers, but when it's a child and in such violent circumstances, it's even worse.

"I cannot begin to imagine what the family are going through, and we have family liaison officers with them trying to answer any questions that they may have.

"At the moment, we are treating it as a murder suicide. We believe the little girl was murdered and the man then committed suicide."

Det Ch Insp Kirk added: "We are not aware of any medical conditions and we are not aware of any family arguments.

"What we are getting back from the mother is that she was happy to go along with it and it was a bit of a treat for her (daughter)."

Police said they were called to the rural lorry park at about 2pm after the HGV company which owns the vehicle said it had not returned to base.