The Department sent Jock Stewart from Pentridge to Wentworth as a temporary replacement for Jim Fletcher who was mourning the loss of his wife and kids, however Jim seemed to be working at the same time as Jock, possibly suggesting Jock was brought in to ease some of Jim's duties.
It is around this time Doreen Anderson has been made a generous offer on her mother's house. Doreen doesn't want to sell, and Jock takes matters into his own hands, when he is promised a cut of the earnings. He persuades Doreen to sell by slapping her around. When Sharon Gilmour overhears this, she tries to blackmail Jock. Jock responds by pushing Sharon down the stairs and murdering her.
Sharon's death was ruled an accident by the Department, however, when Jock is suspended and transferred (119), he gives a very detailed and graphic description of Sharon's death to Judy Bryant who swears revenge on him.
Judy eventually gets her revenge when she discovers he is a client of the massage parlour she is working at after an escape attempt. Jock is arrested, and sent to Pentridge. (172)
After Jocks release, he and Judy run into each other again, when Jock tracks her down at home, and rapes her. Judy runs away and Jock gives chase, but Judy refuses to help him when he falls down a stairwell in a nice bit of irony when Judy declares she's doing it "for Sharon, for Dor, for me and all the other women".
As a result of this accident, Jock is left paralysed, forced to spend the rest of his life confined to a wheelchair.