For those who were wondering – yes this audio was used in a real trial. In fact it was crucial evidence in obtaining a conviction for murder. You can read the case study on this site, including an account of the original perception experiment.
The experiment you participated in sought to investigate some additional questions using the same audio. Please note that, depending which condition of the experiment you were randomised into, the phrases you were primed with may or may not have been phrases used in the actual trial.
UPDATE: Findings of this experiment have now been published, along with a brief editorial giving background reasons for running it. Find the publications at the links below.