More than a month ago, after Kamei Yuusaku was beheaded, Kazama Tatsuya was still unconscious.
Kazama Chihime used a cloth strip to tightly wrap her father's elbow, submerging his forearm in the snow to chill it. When the skin turned blue and purple, she then chopped off his forearm with a single strike.
Afterwards, she smashed things around inside the police car, creating a scene of chaos to fake an intense fight.
The method wasn't sophisticated, but with unclear motives, it was indeed quite effective. The criminal police in the investigation department were misled to think it was an attack by the Heavenly Punishment Group, leading to Kazama Tatsuya losing an arm in the crossfire... perhaps even dead.
In this way, the suspicion on Kazama Tatsuya was barely cleared.
Why was it 'barely'?
Because Kazama Tatsuya was still alive, and being alive meant there was suspicion.