A Harris County grand jury indicted a Spring man on two new arson charges tied to a 3-year-old boy's burn injuries from a deadly July apartment fire.

Matthew Atwater, 38, has been held in the Harris County Jail since the July 20 blaze at the Cypresswood Apartments, located at 4607 Cypresswood Drive, KPRC 2 first reported. He was initially charged with felony murder, with arson as the underlying offense, after his brother Andrew Atwater, 40, died in the fire. The two new indictments are connected to the serious injuries suffered by the boy, identified as Atlas, and his father, Eian. Both charges include an allegation that Atwater used or exhibited a firearm during the crime, according to prosecutors.

The Harris County Sheriff's Office said deputies and multiple fire departments responded to the fully engulfed building around 1:30 a.m. on July 20. Detectives determined Atwater had argued with family members earlier that evening and allegedly set the fire out of anger. He lived in the apartment with Andrew and their mother, who also suffered serious injuries.

According to prosecutors, Atwater initially told investigators he was cooking chicken, became upset and threw a gas can against a wall. He later gave a different account, saying he poured kerosene on the floor and furniture before using a lighter to ignite the fire.

The flames spread to neighboring units. Atlas, who lived in an adjacent apartment, sustained extensive burn injuries. His father, Eian Spayer, suffered severe burns while running through the fire to rescue his son, family members told KHOU 11. Atlas was airlifted to Shriners Children's Hospital in Galveston.

Atlas remains hospitalized. He has a breathing tube and may face additional surgeries, according to the family's GoFundMe page, KPRC 2 reported.

The fire injured 13 people and displaced about 25 residents, according to the Harris County Fire Marshal's Office, as ABC 13 reported. Six of the injured were hospitalized, three in critical condition.

Court records show Atwater received a mental competency evaluation on Sept. 26. He is being held on a $2.5 million bond.

Houston Crime Stoppers director Andy Kahan told KHOU 11 that Atwater had been released on bond in Jasper County about two months before the fire on five charges, including aggravated assault on a police officer.

Atlas' aunt, Raeanna Sandefer, told KHOU 11 in July: "It's hard to feel anything other than just concern for Atlas and Eian."

Anyone with information about the case can contact Crime Stoppers at 713-222-TIPS (8477).