AURORA, Colo. (KDVR) — Police have arrested a woman in a deadly Aurora apartment fire that killed a 5-year-old Monday morning.

According to the Aurora Police Department, 37-year-old Alondra Michel was arrested on a count of first-degree murder. She also faces three counts of attempted first-degree murder and a count of first-degree arson, with more charges expected.

“Early information obtained in the investigation is that Alondra was involved in a domestic violence incident with a resident on the main level of the apartment building,” Aurora Police said in a statement. “Alondra intentionally set something inside of the apartment on fire, which quickly spread to adjacent units, including the second story apartment where the 5-year-old was found.”

Police said “numerous witnesses” and “physical evidence from the scene” helped them “positively” identify Michel. A booking photo was not immediately available.

Family has identified the boy killed as Abner “Choco” Salmeron Jr. They said the nickname Choco comes from the mole on his face. His family started calling him that because it looks like a chocolate mark. A GoFundMe has been created to help with the funeral costs.

Fire officials said multiple people were rescued and three people were hospitalized, including Salmeron, who died at the hospital. The fire burned through 12 units, displacing 31 people — 18 adults and eight children.

Police and fire responded to the three-story apartment building — the Bella Terra apartments at 15320 E. Evans. Ave. — around 1:30 a.m. and found the building fully engulfed in flames.