. >> 16-year-old randolph parker, seen here in the blue shirt,  khaki colored pants, isthe  problem student in 61-year-old melissa's ninth grade english class. she's giving a party that  afternoon in her classroom for an exchange student who's  returning home. although randolph parker had been suspended earlier that day he returns later and paces outside her door. >> obviously through his anger, he wanted to take out revenge, blamed her for the problems he had been having. so he set up a plan, obviously, to come back at the end of the day to attack her or to hit her >> as this last period  progresses, you can see randolp parker, walking up and down the hallway, waiting for the class  to end. he puts on a red bandana over his face and signals to his  cohort, 17-year-old dominic harris, to position himself on  the other side of the hallway. according to police, harris' roó another student into the class  to coax the teacher to come out into the hallway. >