I was on a capital murder case jury once and we tried every possible way to "fit" the facts together that could possibly (even remotely) account for the testimony (including the accused) and evidence; we wanted to give the defendant every opportunity to be found not guilty.  We could not and he was convicted.  But based on the limited information released, I already can project 2 different scenarios where this accused did not do the deeds he is accused of.  One includes the person that took his weapon could have done the first shooting and the accused armed himself with the (first) deceased 's  weapon and about that time one or two of the armed bystanders show up and point a gun at the accused who then has to make a decision to fire first or die.  Many questions that need to be answered and hopefully the police /investigators get it correct.  A tragedy in any case.