Two Taiwanese men and a Vietnamese caregiver have been charged with causing death due to professional negligence after a fire at a home for the elderly in a rural part of Taoyuan City early this year.

Four people were killed and 12 more injured after the fire broke out at about 4am on March 10 at the private residential-care facility in Longyuan Road, Longtan district, in the southern city, as most of the patients had difficulty walking, The Liberty Times reported.

An investigation was conducted by Taoyuan District Prosecutors’ office and completed on Monday. It found that the power supply to the home was halted by Taiwan Power Company due to maintenance work.

In order to maintain visibility during the blackout, a Vietnamese caregiver named Le Thi Mai Hong lit two candles, which were put on cardboard close to flammable objects in two bedrooms on the second floor of the home. Flames from the candles ignited the nearby objects and caused the fatal blaze.

A Taiwanese man and his son, both surnamed Chung, were identified as co-owners of the center. They had allegedly expanded the facility without getting government approval for the second floor, where 16 patients resided. Prosecutors said they were negligent for failing to install fire-safety equipment such as emergency lights or smoke detectors.