An estimated 38 people died early Friday at a psychiatric hospital north of Moscow when a fire swept through the facility.
The state news agency RIA Novosti says it has been told by a "police source" that most of the victims "died in their sleep [from] inhaling the fumes as they were likely sedated by prescribed medicine."
Health Ministry spokesman Oleg Salagay told the news agency that "three people survived a medical nurse led two patients out of the burning building."
According to The Associated Press, "a photograph on the website of the [local] emergency services showed a building consumed by flames. The emergency services also posted a list of the patients indicating they ranged in age from 20 to 76."
RIA Novosti adds that "investigators working at the scene of the fire, which started at about 02.00 am and was put out almost three hours later, consider several possible causes, including a short-circuit, violation of fire safety regulations and even arson. A criminal case has been opened while the head of the clinic and the surviving nurse are being questioned in connection with the incident, Russia's Investigative Committee said."