The owner of a retirement facility and two employees were detained Sunday morning after a fire broke out in a Bnei Brak nursing home, injuring 20 elderly residents Saturday night.

The retirement home staff is being investigated on suspicion of negligence after firefighters reported that the building lacked proper fire safety equipment, and the employees were apparently not present at the time of the fire. Passersby alerted fire and rescue services.

The fire broke out on the third floor of the nursing home at around 10:15 p.m. The majority of the residents were sleeping at the time. As the fire spread, part of a ceiling collapsed. Three of the victims were seriously injured.

Bnei Brak fire chief Shimon Ben-Ner told Yedioth Ahronoth that the retirement home did not have appropriate safety approval, and that the fire department had asked that the facility be closed. He also told the newspaper that a complaint had been filed with police over a forged fire safety approval months earlier.

A senior fire department official also told Maariv that “unfortunately, this is not the only place we have encountered a situation like this. It is a national phenomenon that buildings do not meet our requirements.”