A young boy who was critically injured in a shooting at a Texas megachurch is the son of the attacker, police have said.

Officers identified the assailant, who opened fire during a service at celebrity pastor Joel Osteen’s Lakewood Church on Sunday, as 36-year-old Genesse Ivonne Moreno.

Moreno was named in an affidavit seeking a search warrant for a home in Conroe, about 40 miles north of Houston where the attack took place.

Church Shooting Texas
A woman holds her face as she waits with others outside Lakewood Church, Texas following a shooting on Sunday (Karen Warren/AP)

The warrant was released by the Montgomery County district attorney’s office on Monday.

Police said Moreno had a history of mental illness, including being placed under emergency detention in 2016.

Investigators have not yet established a motive for the attack.

Church Shooting Texas
Emergency vehicles line up outside Lakewood Church (Kirk Sides/AP)

Moreno used an AR-style rifle before being killed by off-duty security officers, police said.

They added that Moreno’s son remains in a critical condition with a gunshot wound to the head.

It is understood the boy, who is thought to be five-years-old, entered the church with the attacker.

A man in his 50s was also injured after being shot in the hip.

Mr Osteen took the helm of Lakewood Church after John Osteen, his father and the church’s founding pastor, passed away in 1999.

The 60-year-old is a leader of what is known as the prosperity gospel, a belief that God wants his followers to be wealthy and healthy.

He is the author of several best-selling books, including, Your Best Life Now: 7 Steps to Living at Your Full Potential.

His televised services reach about 100 countries and renovating his church’s arena cost nearly 100 million dollars (£79.1 million).

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