If a historical time capsule is opened and its contents are damaged before the property's owner is alerted is this punishable

After a time capsule was found in a corner stone of the John A Brashear factory while it was being demolished, the demolition crew tried to call the history center as well as the city, who currently owns the property but their calls weren't answered. The crew decided to open the capsule and put the artifacts which included family photos, in sunlight and touched them with bare hands. The many living relatives of John Brashear as well as the City of Pittsburgh are trying to place the artifacts into a museum but the demolition crew is holding them at an undisclosed site claiming that they are now theirs.