Milgram: Jikken Kangoku to Kanshu no Shoujo

Welcome to Milgram, the experimental prison that will test your ethics. Currently, in this prison, there are five "murderers." The prison guard, Es, is an amnesiac girl who must investigate the reasons they have been locked up. Gradually, their crimes come to light and the pasts are revealed. And even more so, there is the truth behind the mysterious prison. When all sins are laid bare, can you grant forgiveness? (Source: Kadokawa, translated)