A 2017 prosecution of a California doctor charged with possessing child pornography revealed that the FBI had been tipped off by a Best Buy technician the doctor had paid to service his computer; the technician had searched his computer and then provided evidence to the FBI, sidestepping the need for the FBI to obtain a warrant.
UT Austin sociologist Sarah Brayne spent 2.5 years conducting field research with the LAPD as they rolled out Predpol, a software tool that is supposed to direct police to places where crime is likely to occur, but which has been shown to send cops out to overpolice brown and poor people at the expense of actual crimefighting.
AT&T's secret "Hemisphere" product is a database of calls and call-records on all its customers, tracking their location, movements, and interactions — this data was then sold in secret to American police forces for investigating crimes big and small (even Medicare fraud), on the condition that they never reveal the program's existence.
The NSA and US DEA trick contractors working for the Bahamian phone companies into letting them record the full audio of every call placed in the Bahamas, according to newly published Snowden leaks released in an article in The Intercept. The NSA exploits the "lawful interception" system for conducting wiretaps without having to notify phone companies in order to harvest the full run of cellular calls, apparently as an engineering proof-of-concept in order to scale the program up to larger nations. — Read the rest