The self-confessed killer of the aunt of Alexis Sanchez's girlfriend dumped her body in a reservoir after weighing it down with stones.
Roberto Audano, 70, admitted to shooting dead his wife Concepcion Arregui, 59, in Argentina as she was on her way home to her native Chile.
Mayte Rodriguez and her mother Carolina Arregui both appealed for information on her whereabouts after she vanished on February 5.
The 29-year-old actress and girlfriend of the Manchester United star gave her tearful first interview as police planned to search for the body with an underwater robot.