Investigators say that the attacker who opened fire on pupils as they were praying at a church in Minneapolis was “obsessed with the idea of killing children”.

The attacker, who killed two children ages eight and 10 and injured 18 others, did not seem to have any specific motive, according to Minneapolis Police Chief Brian O’Hara.

She “appeared to hate all of us”, the chief said on Thursday, adding: “More than anything, the shooter wanted to kill children”.

Officials have released few details so far about the suspect’s background, but say she previously attended the church’s school and had a mother who had worked there.

The suspect, identified as Robin Westman, is believed to have approached the side of the Annunciation Church, which also houses a school, and fired dozens of shots through the windows using three firearms. Police also found a smoke bomb at the scene.

Witnesses have described seeing children bleeding as they fled from the church, begging for help from strangers.

In a news conference on Thursday, acting US Attorney General for Minnesota Joseph Thompson said “the shooter expressed hate towards many groups, including the Jewish community and towards President Trump”.

The killer left a note at the scene after taking their own life, officials said, but they added that a definitive motive may never be known.

“I won’t dignify the attacker’s words by repeating them, they are horrific and vile,” said Mr Thompson.

Westman’s name was legally changed from Robert to Robin in 2020, with the judge writing: “Minor child identifies as a female”. However, some federal officials and police have referred to Westman as a man when discussing the attack.

Chief O’Hara told reporters that news outlets should stop using the killer’s name, because “the purpose of the shooter’s actions was to obtain notoriety.”

He added that she, “like so many other mass shooters that we have seen in this country too often and around the world, had some deranged fascination with previous mass shootings”.

US officials have warned for years that mass shooting can lead to copycat killings, as killers seek to become famous through their heinous crimes.

Several major news organisations have a policy of not identifying mass killers.

FBI Director Kash Patel has described the attack as “an act of domestic terrorism motivated by a hate-filled ideology”.

In a post on X, Patel said that the attacker “left multiple anti-Catholic, anti-religious references” written on guns and in notes uncovered by investigators.

“Subject expressed hatred and violence toward Jewish people, writing Israel must fall,’ ‘Free Palestine,’ and using explicit language related to the Holocaust,” he wrote.

The killer also “wrote a an explicit call for violence against President Trump on a firearm magazine”.

In their news conference, officials confirmed that the attacker had previously attended the school. Her mother, Mary Grace Westman, previously worked at the school, and has so far not responded to law enforcement’s attempts to contact her.

They also confirmed that three residences associated with the attacker, who was from suburban Minneapolis, have been searched by police.

They said that the church locked its doors before beginning its Mass service, likely saving many lives.

Officials added that the guns used in the attack were all legally purchased, that the killer did not appear on any government watchlist, and that police are not aware of any mental health diagnoses or treatments that she was receiving.

Witnesses and relatives of victims who spoke to the BBC have described harrowing scenes of violence.

Patrick Scallen, who lives near the church, said that he saw three children fleeing the building – one of them a girl with a head wound.

“She kept saying, ‘please hold my hand, don’t leave me’, and I said I wasn’t going anywhere.”

Vincent Francoual, whose 11-year-old daughter Chloe was in the church when the shooting took place, said he tried not to panic after he heard the news.

He called it “sick” that children in the US are trained to prepare for mass shootings.

“We live in a country where we train kids what to do. And she did what she had to do,” he said.

“Here it’s a pattern. It’s no longer a freak accident,” he said of school shootings in the US.

“I told my wife that every morning, when we drop our kids, we don’t know if she’d be back safe.”

Mr Francoual, who is originally from France, said that Chloe is afraid to return to school or church.

In the wake of the attack, several lawmakers, including the Minneapolis mayor, have called for the state to enact a ban on assault weapons.

“There is no reason that someone should be able to reel off 30 shots before they even have to reload,” said Mayor Jacob Frey, also calling for a ban on high-capacity ammo magazines.

“We’re not talking about your father’s hunting rifle here. We’re talking about guns that are built to pierce armour and kill people.”