A Phoenix high schooler was taken into custody Tuesday for allegedly threatening to “blow up a Muslim church.”Police said the boy, whose name is being withheld because of his age, showed up to Pinnacle High School with “several pounds of a white powdery substance.” Law enforcement later determined the substance to be potassium nitrate, a salt-like substance that can be combined with other chemicals to create a flash powder or fireworks. It is readily available and can be bought online.“In and of itself, it’s not a hazard,” said Phoenix police Sgt. Tommy Thompson. “But you mix it with other chemicals, you can ignite it with a fuse.”Police said one of the suspect’s classmates told his parents Monday evening that one of his peers had talked about his desire to attack a mosque. His parents phoned the police, who took a witness statement. The following day, the witness saw his classmate holding a plastic bag containing white power.The school was not placed on lockdown because police determined that the suspect didn’t pose a threat to the school or students. The suspect reportedly remained in custody overnight. "He's looking at some pretty serious allegations against him at this time," Thompson said Tuesday.Cover: Phoenix Police spokesman Tommy Thompson speaks at a news conference, Wednesday, Jan. 9, 2019, in Phoenix, about the investigation of a woman at a long-term care facility who gave birth.(AP Photo/Terry Tang)