CHICAGO — An Illinois agency is investigating neglect allegations after ten children were killed in an apartment fire in Chicago’s Little Village neighborhood. A tenth victim has died after he was taken to Stroger Hospital in critical condition.

The Cook County Medical Examiner’s office said 14-year-old Adrian Hermandez was pronounced dead at 11:12 a.m. Tuesday.

Firefighters were called to the 2200 block of South Sacramento Avenue around 4 a.m. on Sunday, according to Chicago Fire Media Affairs. Officials said many of the victims were already dead when they arrived.

Illinois Department of Children and Family Services spokeswoman Alissandra Calderon said welfare officials are investigating “allegations of neglect,” but declined to provide further details of the investigation.

Questions remain about why there were no adults in the building when the fire broke out, and why there were no working smoke alarms in the building.

Calderon said her agency had prior contact with three of the families who lost children in the fire. At the time of the fire there were no pending DCFS investigations, she said.

Chicago Fire Department spokesman Larry Langford said that the children were “overcome” by smoke and never awoke to escape the fire. He confirmed that nobody else was in the building with the children, who were there for a sleep-over.

Langford said investigators ruled out electrical wiring as the cause of the fire. Investigators learned that children had set off fireworks from the porch and people smoked cigarettes there, Langford said. The fire department is now conducting a “social” investigation to find out what activities might have started the fire.

Mayor Rahm Emanuel tweeted a statement Sunday mourning the deaths.

“The city shares the grief of the families who have lost so many on this day,” the statement read. “Our thoughts go out to not only the families of those who perished but to members of the department who pushed as hard as possible to reverse the deadly fate…”

Around 200 people gathered on the block Monday evening for a vigil. A memorial of white crosses, candles, flowers and balloons was laid near the site of the fatal fire.

Image via Chicago Fire Department