courtesy at the bar

The Delaware Supreme Court overturned a criminal conviction in a drug case where the prosecutor argued that the jury should believe the police and that the defendant is a liar. This is an example of the force with which the Delaware Supreme Court enforces courtesy in the courtroom. I am still searching for a copy of the opinion, if any of you find it please let me know. From the newspaper article it appears that the legal theory was that the word "liar" would so predjudice the jury that they could not decide upon the case in a fair and impartial manner. According to the news report, the Supreme Court suggested that the prosecutor should have said that the defendant was mistaken. As a member of the Delaware Bar, it would be inappropriate for me to comment.