Feds: There are hostile stingrays in DC, but we don’t know how to find them
I work in wireless telecom: Really doubtful "we don't know how to find them". The FCC's enforcement bureau has a set of vans equipped to find unauthorized transmitters. IMSI catchers must transmit and remain on the air. It would be very risky to operate, even briefly, a portable imsi catcher in a briefcase and move it around WA DC, nevermind one that remained in fixed locations for hours. The only other explanation I can think of is being operated from embassies with full diplomatic protections, but that runs the risk of the host county (USA) PNG'ing several staff with 24 hour notice as punishment.Quick edit: Whole US federal agencies have their own TSCM (technical surveillance countermeasures) staff entirely separate from the FCC. It is a job position at the dept of state. Evolved from bug detection and removal in the analog days to now encompass just about everything that can leak data.