Co-op is secretly marking commonly stolen items including alcohol and laundry detergents with invisible “forensic spray” to track them, in the latest crackdown on shoplifting as a new law on retail crime kicks in. The supermarket aims to use the technique across the country having tested it in Manchester and London since last year. The spray, whichhelps the Co-op identify where stolen items are being resold and report it to the police, contains a unique forensic code for a particular location where the items were sold, which also include sweets. Police can then identify which Co-op store the items originated from when investigating physical shops or online stores suspected of reselling stolen goods. Police forces have used similar tactics to track down stolen bikes and valuables, and protect domestic abuse victims . The technique is part of a raft of measures which the Co-op said had helped it cut crime in its stores by a fifth last year.…