Harris County Sheriff Ed Gonzalez identified Francisco Javier Lupian, 32, as the boys' uncle to whom an unattended gun from Monday's shooting belongs.
ORIGINAL STORY: Gun laying around the house handled by 9-year-old when it went off and hit 4-year-old, HCSO says
The sheriff's office said Lupian was visiting family at the home on Guston Hall Lane in west Harris County when the shooting took place. Family members took the child victim to Memorial Hermann Katy, where he was then flown to a hospital in the Texas Medical Center.
In a motion for bail document, Lupian is accused of leaving an unsecured firearm out.
"Defendant's nephew, who is 9 years old, pulled the slide back, pointed the firearm at his 4-year-old brother, striking him in the head," the document read.
The motion filing mentioned that Lupian taught the 9-year-old how to use a specific feature of his weapon.
"The Defendant had previously shown the 9-year-old how to pull the slide on the firearm," the document also read.
Lupian, is charged with possession of a firearm by a convicted felon, records show.
Lupian's prior charges include a 2012 felony evading charge in Colorado County, for which he was convicted and received a three-year prison sentence.
Meanwhile, the 4-year-old remains in critical condition.
In an initial court hearing on Tuesday, a magistrate judge set the bond at $100,000 for Lupian.
The shooting marks another alleged instant where a firearm was accessible to a child. As of April 2021, 13 Investigates counted 67 Harris County cases since a Texas law went into effect in 1995.
A 13 Investigates analysis also showed that adults rarely serve time even after being found guilty.
SEE MORE:13 Investigates: Significant jail time rare after kids get hold of guns
13 INVESTIGATES: Children with access to guns
ABC13's Miya Shay is following the developments in this case. Follow her on Facebook, Twitter and Instagram.