A 5-year-old Texas boy fatally shot his 4-year-old brother in the head when the pair found a gun inside their home, police and relatives said.

The boy, who was shot in Fort Worth just before noon Sunday, was pronounced dead at a hospital, Fort Worth police spokesman Gezim Pollozani told The Post.

Investigators are still trying to determine whether the shooting was accidental or intentional. No charges had been filed as of early Monday, Pollozani said.

The Tarrant County medical examiner’s office later identified the victim as Truth Albright, KXAS reports.

Truth was at home with his older brother and mother at the time of the shooting. Homicide detectives and investigators from a unit dedicated to crimes against children were processing the scene late Sunday, police said.

A neighbor told the Fort Worth Star-Telegram that he didn’t know the family, but regularly saw two boys playing outside the home.

The boy’s mother has five other children, according to an online fundraiser set up to help offset his funeral costs.

Two other children were shot Sunday in separate incidents in nearby Arlington, WFAA reports — including a 6-year-old boy who was in grave condition after being shot in the head by his preteen brother, and an 8-year-old girl shot in the buttocks who is expected to recover in what’s believed to be an accidental shooting.