Jurors were told to put aside the previous convictions of a man accused of murdering a 70-year-old boat owner.
David MacBride, 45, denies killing Robert Saint and dumping his body at sea.
But he has admitted lying to the police when first questioned about the incident.
Lewes Crown Court has also heard he has previous court convictions for dishonesty.
However, summing up yesterday, Judge Richard Brown told the jury the dishonesty charges did not make him more likely to have killed the pensioner.
He told them: "The only possible relevance is the knowledge of the character of the defendant may allow you to judge the truthfulness of his evidence.
"But his convictions are not relevant at all either to the likelihood of him committing this offence or any evidence that he has committed this offence."
MacBride, of Bramber Close, Bognor, is accused of bludgeoning Mr Saint to death aboard his motor cruiser and throwing his body overboard.
The court heard MacBride, a railway guard, had no previous convictions for violence.
He denies the murder charge and said Mr Saint fell in the engine room and banged his head. MacBride told the court he panicked when he realised Mr Saint was dead and threw his body in the water. Two weeks later, it washed up on the Isle of Wight.
The judge said: "The sole issue in this case is did the defendant kill Mr Saint or was it, or might it have been, an accident?
"If you think the defendant's version of what happened on that day is, or may be, true then you will find him not guilty and that is the end of the case.
"If you are sure the defendant lied to you and the defendant attacked Mr Saint and intended to kill him or cause him really serious harm, then you will find him guilty of murder."
The court has heard Mr Saint, of Horsham Road, Steyning, went missing after arranging to meet MacBride on his boat The Sundowner, moored at Birdham Pool marina near Chichester, in September.
MacBride had previously agreed to buy the vessel for £119,000 with banknotes he claimed he found left abandoned on a train.
Closing for the prosecution, Camden Pratt said MacBride was "a man who became fixated with having that boat".
Jonathan Fuller, defending, told the jury: "It is a strange and tragic tale but the burden lies on the prosecution. He (MacBride) is a fellow human being and whether he is guilty or not remains entirely up to you. He is a man with convictions for dishonesty but not for violence."
The judge was expected to conclude his summing up this morning.
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