ARLINGTON-FORT WORTH (CBSDFW.COM) — Three children were shot — one fatally — within hours from each other during three separate incidences in Tarrant County Sunday.

Just before noon Sept. 15, police responded to a shooting call in the 7700 block of Greengage Drive in Fort Worth. When officers arrived, they found a 4-year-old had been shot by a juvenile sibling. The child was shortly transported to a nearby hospital, where they later died.

Around the same time — only minutes away — officers responded to a shooting call at an apartment in the 3800 block of Mahonia Way in Arlington. Upon arrival, police found an 8-year-old was shot in the buttocks.

Police spokesman Christopher Cook said the initial story provided by the victim’s family was not factual, as they reported the girl was shot outside the apartment. During further investigation, officers found a bullet hole inside the apartment as well as a gun.

Cook said there were at least two other young girls present, and the gun — described as a 9mm firearm — was reported stolen from Bastrop, Texas. Police are currently investigating.

And just hours later, around 4:30 p.m., a 6-year-old boy was shot with a rifle by his brother, Arlington police said.

Police said the victim’s brother found an unsecured .22 caliber rifle at the home, didn’t realize it was real and shot the 6-year-old in the head. He is currently at a local hospital in “grave condition.” His sister was also hit by shrapnel but is expected to be OK.

Adults and several children were reported to be at the home during the time of the shooting. Meanwhile, the homeowners claimed they weren’t aware that a rifle was in the home, and that they didn’t purchase the weapon.

During further investigation, the victim’s teenaged brother claimed he bought the rifle used in the shooting.

All three of these incidence remain under investigation.