When Will hears Buck talking about Shawn being upset in Chapter Six, who does Will think is the guy who bothered Shawn at the convenience store? What does Frick say when asked about Riggs?

When Will hears Buck talking about Shawn being upset, Will thinks that Riggs was the guy who bothered Shawn at the convenience store. When asked about Riggs, Frick says he does not know who this is.