Season 4
New enemies appear to block the Tokusou 9. As in the past, the Tokusou 9 hold on to their belief that "the case will be solved at all costs" and put their all into solving cases.
Episodes
1 Gray Suspect Apr 7, 2021 
2 Murder Designer Apr 14, 2021 
3 Best Day Apr 21, 2021 
4 Prayer Apr 28, 2021 
5 Killing Blueprint May 5, 2021 
6 Cursed Picture May 12, 2021 
7 Murder Puzzle May 19, 2021 
8 Hedgehog in a Locked Room May 26, 2021 
9 Flying Suspect Jun 2, 2021 
10 爆弾バスツアー Jun 9, 2021 
11 完全黙秘 Jun 16, 2021 
12 10億の妻 Jun 23, 2021 13 第13話 Jun 30, 2021