A Volusia County man is behind bars, accused of murdering his girlfriend on the Halifax River.
Thomas Prins is being held without bond on charges of first degree murder..
He is accused of killing 28-year-old Crystal Pifer back in August.
Police say Pifer and Prins went boating and the two got into an argument.
Investigators say Pifer jumped off the boat because Prins was beating her.
Officials say she swam to another boat for help, but later returned to Prins' boat.
Eight hours later, her body was found near a marina in Port Orange.