BOYNTON BEACH, Fla. (AP) — Florida authorities arrested two teenagers Friday for making shooting threats against two separate schools, days after the mass bloodshed in Parkland. The cases are the latest among dozens of threats involving students who express to other classmates or on social media networks that they plan to shoot up schools, officials said. A national organization that tracks school threats says it has recorded about 50 a day on average since 17 people were killed in the mass shooting at Marjory Stoneman Douglas High School, compared with about 10 a day on average.The Boynton Beach police spokeswoman Stephanie Slater said that a 14-year-old boy told two other students in a Facetime video call that he was going to attack SouthTech Preparatory Academy.