Not able to be traced back or found again.

पुनः खोजा नहीं जा सकने वाला

English Usage: The evidence was irretraceable, leaving the detectives with no leads.

Hindi Usage: प्रमाण पुनः खोजा नहीं जा सकने वाला था, जिससे जासूसों के पास कोई सुराग नहीं बचा।