They apparently got the local PD to not investigate.
What else would they do?
The Police Chief in Washington at the time the investigation started was Cathy Lanier.
A member of the DC Police force since 1990, she was first appointed Chief in 2007, and had a reputation for being a straight-shooter and a good cop.
Curiously, Chief Lanier abruptly announced her "retirement" in September of 2016.