Goumon Baito-kun no Nichijou

The dark workplace comedy manga takes place in a world where murder and torture are legal and numerous "torture contract companies" exist. Cero and Shiu work part time for the "Spirytus" torture company, which is known for treating its employees well and only targeting bad people. Two new part time hires — Mikke and Hugh — also join the company, and the four enjoy their torture-working life.
(Source: Anime News Network)