Forensic tests have confirmed that schoolgirl Stacey Lawrence was sexually assaulted before being strangled by her mother's boyfriend, who then hanged himself.

Stacey, nine, was found dead in the cab of Darren Walker's lorry in a layby on the A605 in Warmington, Northamptonshire, on Saturday August 29.

Mr Walker, 40, who had taken Stacey out with him as a treat, was found hanged in woodland nearby.

A Northamptonshire Police spokesman said: "The forensic results are back and they did confirm that there was evidence of a sexual assault which is what most people expected, obviously before the little girl died.

"There is no evidence that she had been raped but there was evidence of a sexual assault."

Just before Stacey was murdered, the pair made a stop at a service station. CCTV footage released by police seemed to show that the pair were comfortable together as they browsed the aisles.

The youngster had been on trips with Mr Walker four or five times before, and her mother Roxanne Lawrence, who has three other children, said they had nicknamed her the "baby trucker".

Mr Walker had been seeing Stacey's mother for about a year and only had one police record - a caution in 2006 for assaulting his wife of three years.

It has emerged Stacey was strangled with a ligature of black fabric, thought to be some kind of strapping.

Mr Walker used the same sort of fabric to hang himself in nearby woodland, police said.