Detectives investigating the murder of 13-year-old Lucy McHugh are screening her last known movements to thousands of football fans.
Lucy's body was found in woodland near Southampton Sports Centre early on 26 July.
CCTV footage of her outside a nearby Tesco Express is being shown on the big screens at Southampton's match with Burnley at St Mary's on Sunday.
Leaflets appealing for information will also be handed out.
The CCTV footage of Lucy at the Tesco Express on the corner of Coxford Road and Lordswood Road was taken at 9:30 on the 25th July - 30 minutes after she left her home on Mansel Road East.
Police say it's 'vital' that they trace her movements that day.
The charity Crimestoppers is offering a reward of up to £10,000 for information leading to the arrest and conviction of the person or people responsible for Lucy's murder.
A 24-year-old man from Southampton was arrested on suspicion of murder and sexual activity with a child and was bailed in relation to those offences.
The same man appeared in court on 31 July charged with an offence which relates to failing to disclose a password to his Facebook account to detectives investigating Lucy's murder.
Stephen-Alan Nicholson, of no fixed address, was remanded in custody to appear at Southampton Crown Court on 31 August.