Saavedra was the commander of the throops that massacred 82 settlers on Tarakis. He tried to cover up the massacre, but the details of this crime against humanity were boradcast via a synaptic transmitter.
This synaptic transmitter would cause those who came in contact with it to relive the massacre, so that it would be remembered. The Voyager crew was affected by this transmitter, and would repart it so it would continue to be a memorial to those who Saavedra killed.