A security staff member at Evanston (Ill.) Township High School has been fired after the school board determined that the employee was responsible for a series of locker thefts.

WLS-TV reports that authorities in Evanston are zeroing on in a second safety department employee after both of them appear to have been caught on camera stealing from students' lockers.

School officials sent a letter last week to parents assuring them they were taking the allegations seriously.

They also have established a new policy that limits staff members' access to master keys for student lockers. Only the chair of the physical education department will have a master key, and two witnesses must be present before any student locker is opened with that key.

Video from WLS-TV: