Confessed to the murder of ex-husband, Colin (Nora actually caused Colin's death)
Confessed to the mercy killing of her father.
Melanie was first introduced as one of the doctors treating Viki's breast cancer. She then moved to Llanview to get away from her cheating husband, Colin. She ended up falling in love with Bo, but all the while was being blackmailed by Colin about her father's mercy killing. It was apparently this torture that led her to strike Colin with a poker the night he died, although it turned out that Nora pushing Colin down the stairs in self-defense turned out to be the cause of his death.
Melanie moved into Bo's apartment, but was frustrated by the fact that he appeared in no rush to get married. She tried to prod him into marrying her by sending herself a wedding present from a fake relative. When that didn't work, Lindsay convinced Melanie to tell Bo that she was sick to get him to marry her. Melanie planted a fake medical report saying that she had leukemia. Bo took the bait and planned a quick wedding for them, but at the last minute found out that she was faking her illness. He broke up with Melanie and she moved to Seattle.