This became such a part of their job that the order of railway conductors started warning their members that there's Pinkertons undercover who are watching you.
A prosecutor in Argentina has accused the former President Mauricio Macri of ordering the intelligence service to spy on about 100 people, including political rivals and journalists during his time in office.
The man has a suspicious syndrome, so you've followed him, spied on him for weeks on end, which isn't exactly the highest ethical practice in collecting a history.
I was sure that if he realised that our relationship was—or had ever been-closer than that of headmaster and pupil, he would seize his chance to use you as a means to spy on me.