There is always a reason. It might be a shitty one, but they are in charge, and there aren't any appellate processes for the inmate. The CO can basically levy an accusation of specific charges on any inmate by placing "under investigation". Once that status is tagged, they take the inmate(s) to the SHU until the investigation is concluded. This could literally take weeks or months. There are different commissary rules for the SHU, the item list is very limited.
Thank you for trying AMP!
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