A family member of a 6-year-old boy who died in a Detroit house fire over the weekend is in police custody.

The relative was arrested for alleged child abandonment following the deadly fire, Detroit police told FOX 2. 

The boy had been left alone in the home when the fire started, authorities said. 

Fire crews arrived in the 15800 block of Lindsey on the city's west side around 4:30 p.m. Sunday afternoon, which was within minutes of getting the call. However, by the time they arrived the fire had already engulfed the home.

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6-y-o killed in house fire three

People in Detroit neighborhood watch fire be extinguished, investigation underway,  (FOX 2 Detroit)

At one point during the fire, the boy's mother arrived in a car, but it was too late.

Neighbors said the mother lived at the home with the boy and a dog for about five months before the tragedy. 

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6-y-o killed in house fire two

Crews said the fire was too dangerous to get into the home to rescue the boy.  (FOX 2 Detroit)

"When I thought the boy was in there, it was devastating because I've seen him every morning catching that bus," a neighbor said. "I'm pretty sure every neighbor would have run out and helped if they had known that baby was in that house."

The Bureau of Alcohol, Tobacco, Firearms and Explosives is investigating the fire alongside the Detroit Police Department, FOX 2 says.

6-y-o killed in house fire one

Fire crews on the scene Sunday where a 6-year-old boy died after a fire tore through a west Detroit home he was staying in. (FOX 2 Detroit)

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At this time the cause of the fire is unknown, but authorities believe it started in the front of the home, likely in a bedroom.

Police have not identified the relative arrested, but reiterated the arrest was not for the fire but rather child abandonment.