Location: Maryland - Supervisor At A Federal Contractor Is Telling The Whole Team He Plans To Illegally Dock A Coworker's Pay $600 For Lost Keys. I Want To Report This To Hr. Am I Protected?

Location: Maryland

(Using a throw away and had AI help write this post to ensure clarity)

Hey everyone, looking for some advice regarding Maryland labor laws and federal contractor whistleblower protections.

​A supervisor at my company (we are a federal contractor operating in MD) is walking around telling our entire team that if a missing set of truck keys isn't found, he is going to have $600 deducted from a specific coworker's paycheck to cover the replacement. Strangely, he hasn't directly threatened the coworker yet—he's just telling everyone else that this is exactly what he's going to do.

​From my understanding of the Maryland Wage Payment and Collection Law (MWPCL), you cannot dock a paycheck for lost property without separate, explicit, and voluntary written consent from the employee. Furthermore, we are on a federal contract covered by a prevailing wage determination. A $600 deduction would drop my coworker's net hourly pay way below their mandated contract rate, which violates federal DOL rules (SCA/Davis-Bacon).

​Because my coworker doesn't even know he's threatening this, I want to step up and email HR to blow the whistle on this supervisor's explicit intent to commit a massive wage and compliance violation.

​My questions: ​Am I protected if the threat wasn't made to me, or even directly to the victim yet? Does reporting a supervisor who is openly planning an illegal payroll deduction count as a "protected disclosure" under federal contractor whistleblower laws (41 U.S.C. § 4712)?

Can they fire or discipline me for flagging his verbal statements to the team?

​How should I frame this to HR? Since it's currently verbal "bragging" to the rest of the staff, how do I phrase the email so HR takes it as a serious legal liability and doesn't just dismiss it as workplace gossip?

Do I need witnesses to back up my statements?

​I want to look out for my coworker and stop this violation before they corece them into signing something, but I don't want to lose my job over a rogue supervisor. Thanks in advance.