That's just the way it is.
Frayed knot.
The PROSECUTOR will have to prove his GUILT in a court of law, under a charge of murder.
That's REALLY the way it is.
Really, it's a game of shows. A competition between shows presented to the jury. Or sometimes; who is allowed by the judge to put on the best show.
It's rare that anyone testifying actually tells the truth. Seems like most people that testify have reasons to be deceptive. The most important testimony usually comes from paid experts, police officers, civil executive employees, jail-house snitches and the very guilty who turn on the marginally guilty.
Truth and Reality are usually the first issues to be tossed by the wayside and it becomes - What is the best Show that the jury might buy that can get by the judge and can be created out of all the lies, deceptions and prejudices, etc. -
Sometimes it all comes down to something really insane like "If the glove don't fit you must acquit."
But, unlike that example, it's usually the prosecutor that has the upper hand with money, control of events, witnesses, sympathy of the judge and on and on.