A man was arrested in the northern Mexican state of Nuevo Leon after he confessed to murdering his fiance's mother in a Facebook post, officials said.
Roberto Alejandro Santos, 32, was arrested Sunday and is being held in connection with the killing of 61-year-old Lucila Reyes, Nuevo Leon deputy prosecutor's office spokesman David Perales told EFE news agency Monday.
Reyes's body was found Saturday afternoon at her house in the city of San Nicolas, but investigators suspect she was killed in the early morning hours.
"I did it, I don't know how they can allow me to live another day," Santos said in a Facebook post.
Santos was already a suspect in the case because his fiancee, 25-year-old Julibeth, had filed a complaint with police after he beat her.
The suspect is being held on a preventive arrest order of up to 30 days, prosecutors said, adding that a judge will decide whether to charge him once the order expires.
Santos's confession on Facebook is not enough to charge him and the case will depend on what he tells prosecutors.