The investigation into a bomb threat hoax at a Fond du Lac school this week continues. Police captain Rob Duveneck says investigators are trying to determine who wrote the threat on a bathroom wall at the STEM Academy. Duveneck says even though the threat turned out to be unfounded police take all school threats seriously and respond accordingly. He says a student did the right thing by telling a custodian. “If you see something, say something. The student did the right thing,” Duveneck told WFDL news.