Investigators say a fire that killed two people Sunday in the New Carrollton is suspicious in nature. (James Arkin/For The Washington Post)

A day after a fire raged through a New Carrollton area apartment building, leaving two people dead, police had a suspect in custody facing murder and arson charges.

Details about what happened Sunday night, however, remained unclear.

Authorities say Anthony Andre Allain, 44, faces two felony murder and first-degree arson charges in connection with the fire that roared from a top-floor apartment at 7602 Fountainbleu Drive.

But investigators continued to work to confirm the victims’ identities — they have been called only a man and woman — their relationship to each other and Allain, and the circumstances that led to the fire.

Allain started the fire after barricading the door to the fourth-floor apartment with himself and the others inside, according to Julie Parker, a Prince George’s County spokeswoman. He then jumped to the ground and fled, Parker said.

Authorities said the woman who died was found on the ground behind the apartment and appeared to have jumped to escape the flames. She was taken to a hospital and pronounced dead, according to Parker.

Witnesses said the man who died appeared unable to escape. Firefighters found his body inside the apartment.

Both victims were thought to have lived in the building, Parker said. The apartment that burned was thought to be Allain’s, officials said.

Police found Allain on Sunday night in a basement nearby. He suffered non-life-threatening burns, according to authorities, and was taken to a District hospital for treatment. He will be charged after he is extradited to Prince George’s County, authorities said.

The fire started at 7:45 Sunday night, officials said. Blanche Jackson, who lives across the street, said she heard screams outside her window.

“I looked out the balcony and all I could see was just fire,” Jackson said.

She said she called 911 and then rushed across the street, where a crowd had gathered. A video she recorded on her cellphone showed flames raging on the apartment balcony and spreading to adjoining apartments.

Steve Coates, who lives in a building next to the one that burned, said he ran outside when his building’s fire alarm sounded. He said he immediately saw the fire, which was “a horrific sight. I’d never seen anything like it.”

“Everybody was just in awe,” Coates said. “We just couldn’t believe it.”

Workers boarded up windows and cleared debris from the garden-style apartment into the early afternoon Monday. The fire is estimated to have caused as much as $200,000 in damage and might have displaced up to 50 people, authorities said.

County firefighters were busy Sunday. Authorities said two other fires they responded to were ruled accidental; at a two-story single-family home in Clinton, a firefighter who fell sustained minor injuries.