sb. slang. Abbreviation for DETECTIVE.
1888. Pall Mall G., 11 Oct., 2/1. Tecs and inspectors examine the place, make notes, and go away.
1888. Daily News, 27 Dec., 7/2. Witness seized Wright and said I am a police officer. Wright replied You are no tec; give me a chance, struggled violently, and got away.
Hence Tec v. trans., to watch as a detective.
1900. G. Swift, Somerley, 57. Lets watch the head; he might be a kleptomaniac, or whatever they call it . Id like to tec the head.