A mistrial has been declared in the trial of a man who has confessed to killing a Kirkwood police sergeant.

The St. Louis County Circuit judge declared a mistrial after jurors spent 12 hours deliberating the fate of Kevin Johnson without reaching a verdict. Johnson stunned the jury earlier in the trial by confessing. He previously had denied shooting Sergeant William McEntee. McEntee, 43, died in the summer of 2005 of gunshot wounds. Prosecutors say Johnson killed McEntee, because he thought police had done too little to save the life of his brother, Joseph "Bam Bam" Long.

McEntee was among the officers who responded to a medical emergency call at Johnson’s family home in the Meacham Park neighborhood. Long, 12, collapsed with a heart ailment and died at a hospital.

Johnson confessed on the witness stand that he fired into McEntee’s patrol car, wounding him. McEntee crashed the car. Johnson said he walked to the wreck and fired into the car again, killing McEntee.

The jury could not decide whether Johnson should be convicted of second-degree or first-degree murder. Prison sentences vary greatly between the two. While someone convicted of second-degree murder can serve life in prison, early release would be possible, as well as a much lighter sentence. First-degree murder demands execution or life in prison without the possibility of parole. Prosecutors say a new trail will be scheduled.