what the .... ?! No charges? I don't know about the US, but here in the UK impersonating a police officer, paramedic, etc is taken very seriously.
Not only does it endanger citizens who may rely on the assumed protection and care of that professional, but imposters also bring the service into disrepute if they masquerade as emergency workers and get someone hurt, don't take statements correctly, screw up the legal process etc.
Throw the book at him *grrrrr*