Help Required in Ripping a Japanese android game [The Prison Boys]

[Stryquill]

So apparently there's this game called "The Prison Boys". Its an android game - a mystery visual novel. I looked up on websites etc and searched and concluded to rip the apk games, I only needed to change the extension to a compression file like a ".rar" and then simply extract it. However, upon doing so I donot find any of the sprites used in the game.

Any help/suggestions? The game is about 50.3MB if I am not wrong.

The sprites are 2D like any typical VN: 
I found this from a wiki fandom. The sprites are nowhere available.