Police are due to carry out an autopsy on Monday and have not ruled out the possibility Pilloni was killed, something Mallus denies.
“My mother died of natural causes,” Mallus told the newspaper L’Unione Sarda. “I would never have harmed her.
“When I discovered her body I was desperate. I had no money for the funeral, so I locked her in there.”
Small town in shock
Angelo Dessi, the mayor of Sarroch, said the town’s 5000 residents were shocked and dismayed by the news.
“We live in a tranquil community and it’s a healthy place to live,” Dessi told The Telegraph. “You never think anything like this would happen here.
“We have to reflect on how it could have happened in a community where everyone knows each other. We can’t understand it.”
Sardinian prosecutors have opened an investigation into charges of concealment of a corpse and defrauding the state.
Ivan Murgana, a journalist who lives in Sarroch, said when residents asked Mallus where his mother was he gave various answers.
Police are questioning the dead woman’s doctor and the town’s pharmacy to find out more about the state of her health before her death.