ANY TIME I GET CALLS FROM DC AND THEY HANG UP I GET SUSPICIOUS

Does anyone know this person? Anytime I get calls from DC area cell phones who stutter when I answer the phone and then claim to have the wrong number I get a little suspicious. When trying to find a directory listing all I find is Michelle, but then the phone number for Michelle is picked up but nothing is said until I say hello? an to my surprise the same male voice that called me from the cell phone says hello and claims the number is an unlisted Police number and tells me "you better forget