Who does Will think has killed Shawn in Chapter One? Why does Will think this?

Will thinks that Carson Riggs, Shawn’s best friend, has killed Shawn in Chapter One. He thinks this is because the turf of the gang that Riggs joined includes the place where Shawn was killed. Will also thinks that survival tactics, to beat down before getting beat down. Will also thinks Riggs is the murderer because Will used to solve crime scenes before the cop figured it out and it “had to be” Riggs (73)