Lino Renzi, 45, was found in a state of confusion by police at his mother’s home.
The mutilated body of 70-year-old Maria Pia Guariglia was found in the bathroom, La Città di Salerno newspaper reported.
The police also discovered body parts in the oven, in a cooking pot and in the freezer. It is thought Guariglia was killed two or three days ago, the newspaper said.
Renzi has long suffered from mental illness and has been admitted to psychiatric care in the past.