Chapter 1 - 1 sketch is behind the tree in the first level where you play as young Leon.

Chapter 5 - First classroom level after Leon teleported has 2 sketches. 1 sketch is behind the fallen locker. Another sketch is in the next classroom where you transformed into the doll to enter the small hole.

Chapter 6 - First sewer level, 1 sketch in a secret area where you need to enter a passage under the stairs.

Chapter 9 - Desert sewer area has 1 sketch.

Chapter 10 - Classroom level where Leon meets Kelly. 1 sketch in the first floor.

Chapter 13 -Classroom level where you play as Sara, sketch in the last classroom

Chapter 16 -The tomb area where you have to solve the 2 wheels puzzle. Sketch is in the last area.

Chapter 18 -The flashback area in the tomb where you play as adult Leon. Sketch is on the floor. Not too far from the starting point.