HARDENED detectives were left sickened by the attack on Sophie Lancaster and Robert Maltby.

Senior officers said it was the "one of the worst" cases they had ever dealt with.

During the horrific assault Sophie's hair was pulled so hard that a piece of flesh was missing from her head.

While Robert had been kicked in the face with so much force that lace marks were left imprinted on his face.

The couple's injuries were so bad that emergency workers were initially unable to determine their sexes.

Both were left with heavily swollen faces and bleeding from their ears and noses.

They were found unconscious and admitted to hospital.

Later, Robert recovered enough to be briefly let out of hospital to visit Sophie.

He was discharged on August 24, the day Sophie died.

Police knew who they were looking for almost immediately thanks to the bravery of the yobs' own friends who gave evidence against them.

And blood stains embedded in the trainer treds of one of Sophie's murderers helped police track the brutal mob.

At the height of the investigation around 40 police officers and staff were assigned to the case.

Detective Inspector Dean Holden said: "Ryan Herbert had blood from both victims on his clothes while Brendan Harris had blood embedded in the tread of his trainers, either because he had stamped in a pool of the victims blood or had been stamping on the victim which was consistent with the injuries.

"That forensic evidence put them both at the scene.

"Robert had been kicked so hard that lace marks had been left imprinted on his face but it was impossible to say whose lace that was."