Because their quarters were all sound-proofed, the Titans were only alerted by Kori's scream when she went to check why Tara was late for breakfast.
The room was secure from the inside, Dick noted. There was no sign of a struggle and, frankly, he doubted that anyone could possibly force Tara to do anything that she didn't want to do. The gun was identified as one that Tara had checked out of the evidence room with her key-card and only one bullet had been fired.
In the end, the most damning piece of evidence was the note: "I'm so sorry. I love you Gar. Please forgive me, for that is one thing that I cannot do."
Wilson Slade, even after being sent to hell, had claimed one last victim.