Holly and Jessica's red Manchester United tops and their other clothes were found cut and burned in a bin in an outbuilding of Soham Village College, known as "the hangar".
Police discovered them after finding a set of keys in Ian Huntley's home. He had previously denied having keys to the hangar.
Two of Huntley's hairs were found in with the clothes and his fingerprints were on a bin bag which had been placed on top.
Some 49 tiny fibres matching the girls' shirts were found on Huntley's clothes and around his house.
Fibres from Huntley's carpet and curtains were also found on the shirts, establishing a two-way link between the clothes and Huntley's home.