Transcript for Police foil school bombing plot
80s and 90s, as autumn officially arrives tomorrow. Rob, thank you. And after a tip about a possible bomb plot and a threat of a mass shooting at two schools, a little more than 24 hours later, police had a suspect in custody. What he said about his arrest. Here's Stephanie Ramos. Reporter: Tonight, police say it was a tip that helped lead them to an arrest of this man, who they accuse of plotting against two schools in Pennsylvania. Sorry for what? Making a bad joke. Reporter: But police say Christian Diehl's threats were serious. The 28-year-old was arrested Saturday night for allegedly threatening to use pipe bombs and conduct a mass shooting at a elementary and high school in Hazleton, Pennsylvania. Authorities say they received a tip about the alleged plot. The message indicated it was talking about a manifesto. It was talking about pipe bombs being set around this school, it was talking about this school being a diversion and then having a mass shooting at the high school. Reporter: Officers even considering closing the schools if they didn't have a suspect in custody by Monday. Who knows if we would've shut the school down. Who knows if we would've just put extra patrols in the area. When you have a threat of that nature, you just can't take it lightly in today's world. Reporter: Police say it took 12 hours to apprehend Diehl, who tonight is in jail and being held without bail. Police have not yet executed a search warrant on his home. But Diehl is charged with threatening to use a weapon of mass destruction, which is a third degree felony. Tom?
This transcript has been automatically generated and may not be 100% accurate.