Forensic tests confirmed today 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.
Walker, 40, who had taken Stacey out with him as a treat, was found hanged in woodland nearby.
A Northamptonshire Police spokesman said today: "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 Walker four or five times before, and her mother Roxanne Lawrence, who has three other children, said they had nicknamed her the "baby trucker".
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.
Walker used the same sort of fabric to hang himself in nearby woodland, police said.
Mrs Lawrence previously said Walker had appeared to be "a family man" who was "brilliant" with her children.
She said: "The man that I loved is not the man who did this. This is not the man we knew.
"Obviously the man who did this is an animal. No sane-minded person could do that to an adult or a child."
Losing Stacey was "like losing part of yourself", the mother-of four said.
She went on: "Realising she is never going to come home, and we're never going to see her. Realising she is never going to grow up and have her own children and be the zoo keeper she wanted to be.
"It's just so hard to bear."