A teenager has been arrested for intentionally setting a fire that killed his 10-year-old sister in their Georgia family home, authorities said.

Zoe McCue perished after becoming trapped in her bedroom when the blaze broke out in the Loganville home at about 5 a.m. Sunday, Fox5 reported.

Her brother, who hasn’t been named, was taken into custody Sunday night after police revealed the fire was deliberately lit, the Atlanta Journal-Constitution reported.

No charges have been filed, but cops said they are treating the girl’s death as a homicide.

The home was already engulfed in flames by the time fire crews arrived early Sunday.

The girl’s mother and two siblings had already managed to escape, but believed the 10-year-old and her 15-year-old brother were still inside, authorities said.

“Multiple aggressive search attempts were executed to locate the missing children,” Gwinnett County fire spokesperson Lt. Justin Wilson said.

“After the fire was brought under control, a 10-year-old female victim was located deceased in room used as a bedroom without window access.”

Fire crews spent the next several hours sifting through the debris of the gutted home for the 15-year-old boy.

He was eventually found safe at another location at 9 a.m. and did not appear to be injured, authorities said.

Two family cats were also found dead among the debris.

Two other people who lived at the home — the father and another teen sibling — were at work when the fire broke out, Fox5 reported.

“At this time, it has been determined the fire was set intentionally by a sibling of the deceased victim,” police said.

“This is still an active investigation and is being treated as a homicide. Gwinnett police detectives are working closely with arson investigators throughout the duration of this investigation.”

Fire alarms had been installed in the home but did not activate when the blaze broke out, authorities said.