Blackmailed Phoebe into granting Charles a drivorce
Killed Jason Maxwell (in a struggle with a gun)
Withheld Richard Fields' medication from him, resulting in his death 
Mona Kane divorced her philandering husband, movie director, Eric Kane, when he deserted her and her nine-year-old daughter, Erica. Mona was probably one of the first successful single parents on daytime TV. She dedicated her life to raising Erica but this love and dedication was never enough. Erica blamed Mona for her father's desertion. The other true love in Mona's life was Dr. Charles Tyler, who in 1970, was married to Phoebe. As Phoebe's relentless badgering of Charles accelerated, he turned to Mona for love and affection. Mona blackmailed Phoebe into granting Charles a divorce (one of the grandest gestures she ever made). After his divorce from Phoebe, he and Mona were married and remained hopelessly in love until his death.
Mona was always there for her daughter - even to the extent of the accidental murder of Jason Maxwell. But to Erica, this love was considered interference. When Mona was discovered to have lung cancer (which she conquered), Erica finally realized how much Mona meant to her and how lonely and empty her life would be without her. The day of Mona's funeral in Pine Valley was one of the saddest days on AMC's history. Erica, who had been unable to show her emotion, hurled herself onto her mother's coffin and cried hysterically.
Throughout her 24 years on AMC, Mona Kane Tyler, kept MANY dark secrets about Erica, while always trying to help Erica nourish the good Mona knew was inside her daughter. Mona was a friend and confidant to many, including her best friend, Myrtle Fargate. Myrtle has tried to be a mother figure to Erica since Mona's death. Mona will always be remembered as what a mother, wife, and friend should be.