From Rockwall Police Department:
The Rockwall Police Department has been made aware of criminals calling residents posing as officers and threatening them with arrest unless payment is made for outstanding traffic warrants. To be clear, most of the legitimate correspondence violators receive will be in the form of US mail or a door hanger. If you are called, the warrant officer will never ask for payment over the phone, but will instead direct you to call the Rockwall Municipal Court directly at 972-772-6478 and ask for the warrant clerk. Additionally, we will not ask for payment in the form of bitcoin or gift cards. If you are ever suspicious about a caller, hang up and dial the court directly at the number above to get proper help regarding outstanding warrants.