Just a bunch of theorieshttps://abs.twimg.com/emoji/v2/... draggable="false" alt="😅" title="Lächelndes Gesicht mit offenem Mund und Angstschweiß" aria-label="Emoji: Lächelndes Gesicht mit offenem Mund und Angstschweiß">

Shigemaru& #39;s scientist partner is probably from the Mizuo Future Technology. They probably had a dispute about their research which caused the murder of Sayuri and "suicide" of Shigemaru. Shigemaru probaby knew that-

something bad was gonna happen , so they hid the files containing the research and the couple separated for a while. They left Daisuke with his grandmother since the enemy may catch on if the three of them were all away and he would be safer there than with them. The grandmother-

probaby knew of this plan too. Sayuri bought a place to stay in and hide. The day or night she died, Shigemaru must have visited and checked on her. After he left, she was murdered. Then the place was ransacked -

because the murderer was looking for the research files. With the murder of sayuri kambe now out, shigemaru knew he& #39;d be the prime suspect and be the next target of the killer. But was unfortunately he was found and (1)murdered as well, making it seem like suicide.

(2)already planned to kill himself if things went south. So as to be a dead end and no else would know about the research files. Unfortunately, Cho-san found the key to storage locker and Takei gave it to the director, giving it to the enemy or the boss.

(3) made to seem like he commited suicide, but is actually alive going undercover or (4) enslaved at Mizuo Future Technologies. Why would Daisuke ask this, as if he believes his father is still alive and hiding and is at Mizuo Future Technologies.

The police and the Mizuo Future Technologies seem have had a connections for a long time. Most likely about weapon manufacturing. The enemy was probably also using the info from the investigation to search for Shigemaru. And the police would cover it all up.