There is no doubt that Yolanda Saldivar pulled the trigger and killed the beloved Tejano superstar Selena Quintanilla Perez. But does any of us know what really happened in Room 158 of the Days Inn, moments before Yolanda fired the gun that took Selena's life?

Maria Celeste Arraras has many answers - and her unrivaled coverage of the murder, the trial, and the aftermath for Univision's Primer Impacto have made her the undisputed expert on the Selena case.

Now Arraras shares first-hand details and facts about the crime and the people involved - including never-before-published details of her headline-making jailhouse interview with Yolanda, who repeatedly spoke of "Selena's secret" - a powerful hidden piece of information that she refused to divulge in the courtroom but revealed to Arraras at length.

Many questions were raised - and not all were answered until now. Why was there a suitcase filled with Selena's clothes at the murder scene? What was the significance of the jeweled ring, adorned with the initial "S," that fell from Selena's bloody fist? Who was the doctor from Monterrey who called himself Selena's confidant and business advisor? And what will become of Selena's secret diary that Yolanda claims to possess?

Filled with original reporting, Selena's Secret fits together the pieces of this puzzle so that, finally, a clear picture of what really happened on that rainy day in March emerges. It's also an intimate portrait of the lives of those people who were most affected by Selena's murder.