Police are investigating the cause of death of an elderly woman found dead in a sauna at a shopping mall in Pak Kret district of Nonthaburi on Monday evening.

Police were informed of the death of the 68-year-old woman at a mall in tambon Bang Talad about 6pm on Monday. She was identified only as Thanchanok. The mall was not named.

The body was in a sauna behind a fitness club. Staff said the woman was a regular customer who paid daily visits.

She had arrived at 8am on Monday. About 11am, staff could see no sign of her and assumed she had left.

About 6pm an employee found the woman lying in the sauna. Parts of her face, arms and breast were severely burned and skin had peeled off her.

Her daughter-in-law said Thanchanok might have died hours before being found. The woman had no underlying illness she knew of, usually visited the fitness club alone and stayed there from 7am to 2pm, she said.

Police were waiting for autopsy results.