A 72-year-old Taoist practitioner died Saturday after being treated for suspected food poisoning which also sickened 11 others at a Taoist temple in the central China city of Macheng, Hubei Province.

Four in critical condition were transferred to the provincial capital of Wuhan for treatment while police had launched an investigation to determine the cause, local officials said.

The victims, all Taoist practitioners at the Emperor Temple of Wunao Mountain, said they suffered from stomachaches, headaches and dizziness after eating porridge and cucumber for breakfast Friday morning. Some vomited and fainted, police said.

It is not clear whether the food had deteriorated or was deliberately poisoned.

Health authorities in Macheng have ordered a thorough investigation of the case and city-wide food safety checks.