To some, Nicole ("Nikki") Addimando is a young mother who shot her abusive partner in self-defense when she feared he would take her life. To others, she is a murderer who took the life of Chris Grover, a father and popular gymnastics coach in Poughkeepsie, N.Y. Now, 48 HOURS and correspondent Jericka Duncan investigate their relationship and the night Grover died in "The Case Against Nicole Addimando."

Megan Waterman was one of the first victims of the Long Island serial killer found by police. In December of 2010, four women - aged 22 to 27, similar in height, weight, hair and eye color - were found dead along a stretch of Ocean Parkway near Gilgo Beach on Long Island, N.Y. They became known as the "Gilgo Four." Now, a decade after Megan Waterman's body was found, her teenage daughter talks for the first time on television with 48 HOURS correspondent Erin Moriarty.