special investigation branch 

The undercover investigative element of the British Royal Military Police. An organisation that is supposed to blend into the wider military community to mirror the effect that CID provide to civil police. In reality it is populated by a bunch of barely literate mouth breathers who spend all day taking screenshots of Facebook and being outsmarted by even the slowest witted squaddie. Most likely military group to be Swingers.

In Special Investigation Branch office:
SIB: "Look sunshine, we know you did it, confess or else"
Perp: "I didn't do it"
SIB: "Oh, you sure? Well, you'd better get out of here, we'll be watching you"
Perp: "L8rs"

special investigation branch by Bumsnorkler March 15, 2019