Marcus was stabbed to death by Heather when he tried to rape her.
Dr Marcus McKenzie was the doctor who performed the life-saving operation on Franco Rossi. His charming bedside manner didn't go unnoticed by Gina and the girls. It wasn't too long before he asked Gina out on a date. At first all seemed to go well between them until Marcus wanted to take their relationship further, but Gina wasn't ready. He didn't take no for an answer, though, and raped her. Unbelievably, he also tried to attack Ruth a few months later.
Jo publicly revealed that Marcus has raped Gina and he became increasingly edgy when he realised the Rossi family weren't going to let him get away with the attack, but thought that a supportive wife would help his image. He asked Heather to marry him, but when she finally realised he was guilty and refused, he attacked her too. Unfortunately for Marcus, Heather fought back and he died after she stabbed him.
Even after his death, Marcus and his family continued to cause trouble for the Rossis. Before Heather's trial, Marcus' daughter Steph came to Shieldinch, desperate for revenge. When Jo sensationally 'admitted' in Court that she'd murdered Marcus and Heather was acquitted, Steph snapped and stabbed Jo.