This is done in Episode 5: Colorado, USA. You will need to use the point man disguise to kill Rose and Pervati with the ram. Next, obtain a militia disguise and the basement key from Berg's garage. Remember to grab the wrench from the toolbox. In the basement, secretly administer a dosage to the hostage. Return to Berg's garage and use the wrench to loosen the valve on the gas canister. Wait for Berg to return and blow himself up. Finally, retrieve the interpol badge and disguise from the specific guard in the apricot farm. Approach Graves and talk to her. You will lead her to the slurry pit, where after another conversation she will tell her guards to go away. She will then lean over the rail of the pit, at this point push her in and you are done.
Here is a video guide with English commentary for this achievement!
Here is a playlist of guides for this game!
https://www.youtube.com/playlist?list=PL-HeW6XkKdUK9Qh-6TvL3...