It really wouldn't have mattered in this particular case. His defense attorney didn't disagree Fowler killed the guy; the argument was for a lesser 2nd Degree Murder charge only. The prosecution wanted 1st Degree, which would have put him in prison for life without parole and his attorney wanted 2nd, which would have only been 15 or so years and then parole. The whole argument is over deliberationand intent.

Did Fowler think about killing the guy before he came to the business to pick up his check, or was it the heat of the moment at the time and he grabbed a gun and shot him? That was the whole issue here.