Checkmate (Tokyo Revenger)

[Mystery Stories Series #2]
The loud sound of sirens echoes throughout the whole Sano residence. Everyone in the manor was frantic. The maids and the butlers are baffled and terrified, and the executives are in havoc. What may have transpired inside the lavish manor, that caused quite a commotion to the residents?

Sano Manjiro, the CEO of the Bonten Company and one of the richest men in Asia, was found dead in his lavish manor right around the residential areas of Shibuya.

Sano was found dead by one of the maids of the manor, his dead body was found lying at the grand staircase of his manor bathing in his pool of blood. Sano was shot three times, leading to his demise.

The air was heavy and dark, despite the superb inside of the manor. The manor screamed tension.

Who killed Sano Manjiro?