At the beginning, when Tali was first taken, there was the head of the department "I just took over last week. I'll look into it. Send me her photo". That guy set up the raid (back dating and essentially forging a signature to make it look like the order was authorized before the guy took over). He was a White Supremacist (WS). While they were investigating someone else, they stumbled upon him as being part of it, so they interrogated him (possibly it was "investigating him (in general), found he had connection to some WS that was a "person of interest", then interrogated him to find out more).