HOUSTON  — The shooter who opened fire at a Texas megachurch on Sunday before being killed by security officers had a history of mental illness and used an AR-style rifle in the attack that also critically injured their 7-year-old son, authorities said Monday.

Genesse Ivonne Moreno was identified by Houston Police Commander Chris Hassig as the shooter at Lakewood Church during an afternoon news conference.

Hassig noted that Moreno, 36, sometimes used both male and female aliases, but investigators determined through interviews and past police reports that Moreno identified as female.

Hassig and others said Moreno had a history of mental illness, including being placed under emergency detention in 2016, but provided no additional details.

Houston Police Chief Troy Finner said it remained too soon to identify a motive for the shooting, but officials said they were looking into a dispute involving Moreno and the family of Moreno’s ex-husband, adding that investigators also found antisemitic writings by the shooter.

Hassig also said Moreno’s rifle had a “Palestine” sticker on the buttstock. He described Moreno as a “lone wolf” who was not acting as any part of a larger group.

“We believe (Moreno) acted alone,” Hassig said.

Police on Monday also searched Moreno’s residence in Conroe, about 40 miles north of Houston.

According to investigators, Moreno and the boy entered the church building at 1:55 p.m. after Moreno pointed a gun at an unarmed security guard and began firing once inside.

The guards inside the building — off-duty Houston police officer Christopher Moreno and Texas Alcoholic Beverage Commission Agent Adrian Herrera — returned fire and killed Genesse Moreno.

All of the gunfire was in a church hallway and none of the violence spilled into the main sanctuary, Hassig said, describing the confrontation as a “gun battle” that lasted several minutes.

“They held their ground in the face of rifle fire at point blank range,” TABC Chairman Kevin Lilly said. “They were a wall that existed between worshippers and terror.”

Both officers discharged their weapons, but investigators do not yet know if Moreno’s son was accidentally shot by one of them, Finner said. The boy remained in critical condition with a gunshot wound to the head, authorities said.

Police said a 57-year-old man who was shot in the hip during the shooting has been discharged from the hospital.

Lakewood is regularly attended by 45,000 people weekly, making it the third-largest megachurch in the U.S., according to the Hartford Institute for Religion Research.

Osteen said the violence could have been worse if the shooting had happened during the earlier and larger late Sunday morning service.