The tragedy killed at least 17 residents, and more are left injured or unaccounted for after the dormitory part of the wooden, tin-roofed structure burned to the ground.

At least four survivors are currently in the hospital, being treated for serious burns sustained during the fire. Of those who died, however, several have yet to be identified.

The “Beautiful Dusk” facility is in Mexicali in the state of Baja California, which is right near the border Mexico shares with California.

The mayor of Mexicali, Jaime Diaz Ochoa, said that the fire’s source is suspicious and investigators are treating the incident as an arson case. Firefighters found no electrical wires or fuel that may have started the blaze.

“In the area where [the fire] started there are… boxes, which by themselves could not have started the fire,” Diaz Ochoa told Mexican TV network Televisa on June 24.

Fires in homes and other types of residences break out once every 85 seconds in the United States, equaling about 1.24 million fires per year and often forcing residents to evacuate through home or commercial windows and doors. For those with limited mobility in nursing homes, however, it’s easy to get trapped if no clear exit is present.

Although no one has been arrested or charged yet, there is some debate over whether the workers at the facility had anything to do with the blaze.

According to Diaz Ochoa, investigators are trying to determine whether the administrators at Beautiful Dusk may have started the fire. The home is run by a nonprofit organization, Sociedad Cultural Impulsora de Bienestar Social A.C (or Cultural Society for the Promotion of Social Welfare), which is also in charge of several other nursing homes in the area.

Diaz Ochoa said that representatives informed investigators that there was a dispute for control of the nursing home. Three caregivers and a security guard were reportedly in the building at the time of the fire, but none were injured, according to reports.

The nonprofit group in charge of the facility and others in Mexicali give “humanitarian assistance to low-income elderly people in need, including food, shelter, clothing and medical care,” according to a government website.