A six-year-old pupil who shot his teacher used a gun that belonged to his mother and was legally owned, police have said.

Authorities said there was no fight or physical struggle before the boy opened fire on Abby Zwerner as she taught a lesson at a school in the US state of Virginia.

Police chief Steve Drew said the boy had taken the 9mm handgun from his family home in a backpack on the day of the shooting.

Providing the first detailed description of a shooting that has shocked the city of Newport News and a country now accustomed to gun violence, he told a news conference: “What we know today is that she was providing instruction. He displayed a firearm, he pointed it and he fired one round.”

Mr Drew had previously said the shooting was not accidental and had declined to elaborate.

He said he wanted to clarify remarks he made just after the incident on Friday, when he said there was an “altercation” before the shooting.

The officer said it was more like an “interaction” between the boy and his 25-year-old first-grade teacher at Richneck Elementary School.

But he also reiterated that the shooting was “not accidental.”

“It was intentional,” he said.

Teacher hailed a hero

Ms Zwerner put up her hand in a defensive position when the weapon fired, and the bullet went through her hand and into her upper chest, Mr Drew added.

While her injuries were initially considered life-threatening, she has improved and is currently listed in stable condition at a hospital.

Mr Drew hailed Ms Zwerner as a hero for quickly ushering her students out of the classroom after she was shot, saying surveillance video showed she was the last person to leave her classroom.

“She made a right turn and started down the hallway, and then she stopped… She turned around and make sure every one of those students was safe,” the police chief said.

Mr Drew said a school employee rushed into the classroom and physically restrained the boy after hearing the gunshot.

He said the boy became “a little combative” and struck the employee, but police officers arrived and escorted him out of the building and into a police car.

The child has been held at a medical facility since an emergency custody order and temporary detention order were issued on Friday, Mr Drew said.

He said a judge would decide what the next steps are for the boy. His mother has been interviewed by police, but it is currently unclear whether she could potentially face any charges.

As questions loomed about the child and his mother, Ms Zwerner’s friend told a crowd gathered at a vigil on Monday night that the first-grade teacher has shown “dedication and love for what she does day in and day out”.

Rosalie List, a 2nd grade teacher at Richneck, said: “Abby is a warrior and she demonstrates mental and physical strength every day. I’m so proud of her.”

Lauren Palladini, Richneck’s school counsellor, told the crowd that Ms Zwerner was “sweet”.

“She’s thoughtful. She’s caring. And she’s been one of the most amazing teachers that I’ve been blessed to interact with,” the school counsellor added.

Amanda Bartley, who teaches at another elementary school in the city, asked everyone to pray for the injured teacher and to “pray for the young man who did this.”

Speaking to reporters, she said many questions remained unanswered.

She said: “How did he get the gun? Why wasn’t it locked up? A good gun owner knows that you lock up your weapon. You have a safety on. You keep the ammunition separate from the weapon itself.”

What will happen to mother and boy now?

Gun owners can be prosecuted under a Virginia law that prohibits anyone from recklessly leaving a loaded, unsecured gun in a manner that endangers the life or limb of children under 14.

A violation of that law is a misdemeanour, punishable by a maximum jail sentence of one year and a maximum fine of $2,500.

Virginia does not have a law that requires unattended guns to be stored in a particular way or a law that requires gun owners to affirmatively lock their weapons.

“Virginia definitely has a weaker law than many other states that have child access prevention laws,” said Allison Anderman, senior counsel and director of local policy at Giffords Law Centre to Prevent Gun Violence.

Legal experts said that even though it was theoretically possible under Virginia law to criminally charge a six-year-old child, there are numerous obstacles to doing so and that it was highly unlikely that any prosecutor would even try.

“It’s virtually impossible to imagine a six-year-old being found competent to stand trial,” said Andrew Block, a professor and the University of Virginia School of Law, who was the director of Virginia’s Department of Juvenile Justice from 2014 to 2019.