The LGA secrets collection consists of 2 secrets, both are SuspiciousMan. The SuspiciousMan is a bot that randomly appears in different areas around vside. Therefor if you get to a spot and the SuspiciousMan is not there, just wait for him. The SuspiciousMan also sells Edoc shirts, which are the shirts you need to enter the murderhouse and complete the RJ secrets.
SM on the Subway Roof
Head to Kong and jump onto the ledges next to it. Walk to the walk, hop up, and go right. Walk straight ahead and jump onto the ledge. Jump down onto the rooftop and head for the edge. Jump down to the subway roof. Walk down to where it drops, but DONT jump down. (It's okay if you fall, you can jump back)
SM Alley Rooftop
Head for the alley behind Degrassi. Click the arrows to climb onto the fire escape.
Now go up. Hop onto the rail and head to the next flight.
Click the arrow to climb over. Jump behind the sign. Look up and to the left and click the arrow(s) to climb up. Head to the right and up the steps.
Now turn around and jump onto the corner of the small wall. Look up above the yellow/orange building and click the arrow to climb up. Walk straight and turn right.