Coroner William Armstrong ruled John Didier, 41, "unlawfully killed" Annette Creegan, 49, the Eastern Daily Press reported. Armstrong ruled Didier's death a suicide.
The bodies of Creegan and Didier were found Sept. 2, a day after a ranger found Creegan's 13-year-old daughter alone on a rented boat moored in the Broads, a series of rivers and open water areas in Norfolk. The girl told police her mother had disappeared several days earlier and she remained on the boat with Didier with no means of leaving or of communicating with anyone.
She said she woke up Sept. 1 to find herself alone.
Creegan, who had been strangled, was naked and her body had been weighted, investigators said. Didier also had weights attached to his wrists and ankles.
"What a grotesque irony that this happened in the idyllic setting of the Norfolk Broads -- what a contrast between the calm serenity of the waters and this dreadful tragedy," Armstrong said.
Didier was originally from Ohio and had settled in England. Creegan was a nurse who worked at a hospice in Clapham Common, a district in southwest London.
Members of their families attended the inquest.