A man charged with murdering his girlfriend says she choked to death on his penis.

Police mugshot of Richard Henry Patterson

Police mugshot of Richard Henry Patterson

Richard Henry Patterson, 65, is accused of strangling Francisca Marguinez in Margate, Florida, in 2015 but has insisted that she died while giving him oral sex.

Patterson was arrested by police after he messaged his daughter and a friend and seemingly admitted to a crime, saying he 'did something bad' and that he 'was so sorry' and had 'choked Francisca', but he now swears he didn't strangle.

Patterson has sworn that he didn't deliberately kill Marguinez, whose body was found face down on their bed with semen stained tissues around it and showed no signs of trauma, but that she died pleasuring him.

However, her body had already began to decompose and so the coroner was unable to determine how she died.

Patterson has insisted that he shows the jury his penis or a mold of it be used as evidence in court and thinks they'll believe his version of events when they realise its size.