An Oahu grand jury indicted William Plourde, a former teacher at the Sacred Hearts Academy of Honolulu, on six counts of third-degree sexual assault and one count of first-degree sexual assault involving a 15-year-old student. The 53-year-old Plourde is in custody on $200,000 bond.  A Circuit Court plea and arraignment hearing will be held once he is served with a bench warrant.