The threats were allegedly made in group chats and social media messages against charter schools River City Science Academy, IDEA River Bluff Charter School, and IDEA Bassett Charter School.
Collin Griffith, 17, is in custody after allegedly killing his mother, Catherine Griffin, 39, on Sunday, according to Polk County Sheriff Grady Judd.
Clinton "CJ" Robinson, Jr., 38, has been charged with first-degree murder, tampering with evidence, and a slew of drug-related offenses.
Doctors told detectives that the seven-year-old boy appeared to be dead for quite some time.
