(WPXI) – A mistrial has been declared in the case of 34-year-old Christian Bey, the man accused of shooting and killing an off-duty Pittsburgh police officer in 2019. A witness for the commonwealth mentioned they knew Bey because he had been in and out of jail. One of the stipulations was that Bey’s prior convictions could not be brought into this trial. Bey was accused of shooting and killing off-duty Pittsburgh Police officer Calvin Hall at a street party in Homewood in 2019. Bey will face a retrial. No date has been set. The mistrial was declared just one day after the trial began. The prosecution and defense made their opening statements to the jury Tuesday morning.