Tracy Reid, Danielle and Lee Gaytor

Lee Gaytor, 25, pleaded guilty at the High Court in Perth to murdering Danielle Reid at a house in Argyll Street, Inverness.

The child's mother, Tracy Reid, and Gaytor's brother Christopher, admitted perverting the course of justice by helping to dispose of the body.

Highland Council, whose social work department had been involved with the case, admitted the tragedy had revealed the need for improvements to policies, practices and procedures.

However, the authority's chief executive Arthur McCourt said he was satisfied with the overall actions of both Danielle's school and social work staff.

Danielle had not been seen in the town since last October when her mother withdrew her from school and told teachers the family was relocating to Manchester.

To most officers there were deeply distressing aspects to contend with whilst remaining focused on the work to be carried out Det Insp Steve MacKay

Advocate depute Robert Anthony QC told the court that on 31 December, Christopher Gaytor was drinking in the Keg Bar in Inverness when he met Hugh McGrogan, Tracy Reid's stepfather.

Gaytor told him that Danielle had been "done in".

After being arrested, Christopher Gaytor, from Hull, told police that he and Tracy Reid had helped put a suitcase containing Danielle's body, into the canal.

When it was retrieved in January, the suitcase was found to have been weighed down with stones, tiles and bricks.

Vodka claim

Gaytor also told police that his brother claimed that Danielle had drunk half a bottle of vodka before falling down the stairs.

The court heard that at least four heavy blows had been landed on the child by 12-stone unemployed Lee Gaytor, who later claimed Danielle was "possessed".

Her head and clothes were covered in blood and stains were found on the stair banister, the hall walls, on a chest of drawers, mattress, duvet and bedroom walls.

Christopher Gaytor: "Danielle has been done in"

Danielle sustained severe brain trauma, but could have survived if she had been given medical treatment.

Detective Inspector Steve MacKay, of Northern Constabulary, said the case was the most harrowing he had seen in his 19 years in the police.

He said: "To most officers there were deeply distressing aspects to contend with whilst remaining focused on the work to be carried out.

"I think I have to make mention of their professionalism and dedication throughout the duration of the inquiry."

DI MacKay went on to thank the members of the public who had been "extremely helpful" in giving details of Danielle's life.

All three convicted are due to be sentenced at the High Court in Edinburgh on 11 July.

Lee Gaytor faces a mandatory life sentence. He and Reid were remanded in custody.

She and Christopher Gaytor, who was released on bail, face a statutory maximum of 10 years in prison for attempting to defeat the ends of justice.