A not guilty plea was entered on behalf of Nora T. Nelson by her lawyer during her arraignment Friday in the Charlestown division of Boston Municipal Court.

A 24-year-old named a “person of interest” in connection with the death of a man on a luxury houseboat in Charlestown now faces a murder charge, prosecutors said Thursday. Nora Nelson was arrested at the scene of the man’s death on Sunday night on a trio of warrants charging her with a variety of domestic violence offenses unrelated to the Charlestown case.

A distraught friend of the victim said he was a Boston lawyer and a divorced father of three. Sources said his dog was also found dead in the harbor.