You can submit an online police report.

https://www.providenceri.gov/police/citizens-online-police-reporting-system/

They could be using them for anything from stealing tools from Home Depot to a drive by shooting so getting that report in before it happens you you don't become a suspect. Then you will need to use that report to go to the DMV and get new plates.

https://dmv.ri.gov/registrations-plates-titles/license-plates/lost-or-damaged-plates