explaining that "[t]o reverse a conviction, the evidence of the defendant’s election to remain silent must point directly at the substance of the defendant’s defense or otherwise substantially prejudice the defendant in the eyes of the jury."

allowing admission of bag containing sheet of black plastic upon which murder victim was found on basis that its probative value, in supporting state's theory that the defendant had attempted to conceal and dispose of the body, was greater than any prejudice resulting from its "strong, nauseating odor which permeated the court room"