The Plot Predicate Was Weak (Spoiler)
If Larry had told the truth about his fight with his girlfriend's husband, he would have had nothing to fear from the law. The husband was a serial bigamist and blackmailer. During the confrontation, the husband pulled a knife on Larry and he had no choice but to defend himself. There is always the "if only..." or "if not for..." that sets up the drama to follow. However, I think when you have the law on your side and all you have to do is tell the truth, it is foolish to create problems by manipulating evidence and staging a cover-up.
Moreover, the husband's death was an accident because he fell and hit his head. Larry never deliberately tried to kill the husband. I thought it interesting that his brilliant lawyer-made-judge brother Keith didn't advise him of this, especially after he learned that the husband was a bigamist and conman.
This points up the notion that contrary to most descriptions, Keith was actually the weaker character. Larry had a moral compass that brought him back around to true north and he was willing to sacrifice his comforts in the interest of justice. On the other hand, Keith was motivated by selfishness as he tried to perpetuate the falsehoods to save his own career.
As a man thinketh in his heart, so is he. - Proverbs 23:7