Waterloo police have made a seventh arrest in an October shooting rampage that left one woman dead. 56-year-old Paul Ackerman of Waterloo was charged yesterday with accessory after the fact. Police believe Ackerman was involved in the disposal of a weapon that was used in the incident. On October 10th, a group of men in a car opened fire on a Waterloo house in an apparent attempt to scare people at a party. During the shooting spree, one of the bullets hit and killed Thyanna Parsons, who was inside the home. Ackerman is being held in the Black Hawk County jail on 100-thousand dollars bond. The six other men charged in the shooting, all from Waterloo, are each charged with first-degree murder.