NEW : 2 possible suspects are in custody , a Memphis police sergeant says . NEW : There was a loud noise after a bomb threat was made , according to police . The FBI is investigating the threats and has asked local law enforcement for help. The injured person was taken to Methodist North Hospital in Memphis , Cook said . It appears to be a prank , a school spokeswoman says .
NEW : 2 possible suspects are in custody , a Memphis police sergeant says . NEW : There was a loud noise after a bomb threat was made , according to police . The FBI is investigating the threats and has asked local law enforcement for help. It appears to be a prank , a school spokeswoman says .