Nicole Brown Simpson's Sister Hopes To Raise Awareness About Domestic Abuse

It has been 32 years since Denise Brown took the stand at the murder trial of O.J. Simpson, and testified about his history of beating her sister, Nicole Brown Simpson. Now, Denise tells ABC News' Diane Sawyer that the nation needs a fresh lesson in how domestic violence can escalate. Denise is urging victims of domestic abuse to heed the warning signs before it is too late. Denise is speaking out as she releases her new book, "For My Sister Nicole: Love Shouldn't Hurt."