A teacher who was shot by a teenage gunman in a Bend, Oregon, elementary school last week said she saw the attacker and tried to shut the classroom door, “but the shooter was already there.”

Becky Drury said she was shot at close range in the rampage at Silver Rail Elementary School on Thursday.

“Lying on the floor, I saw that my left hand was almost completely severed from the gunshot, and my other arm was also severely injured,” Drury said in a statement Wednesday.

“I could not get up, defend myself, or protect anyone else,” she said. “So, I did the only thing I could do, which was to pretend to be dead in the hope he would not shoot me again.”

Three children, ages 5, 8 and 11, and a 25-year-old teacher were killed in the attack, which began around 1 p.m., officials said.

The gunman was fatally shot by a bystander who saw him fire at a truck and enter the school, police have said. The bystander followed the 16-year-old gunman and shot him as another teacher was wrestling with him over the weapon, according to police.

The motive remained under investigation Wednesday.

Investigators are looking into whether the shooter viewed any extremist material online, including material associated with “nihilistic violent extremism,” also known as NVE, two senior law enforcement officials briefed on the investigation told NBC News.

The gun was purchased legally, Bend police said in a statement Wednesday.

Police have said that it was a Maverick 88 pump-action 12-gauge shotgun and that the shooter used birdshot, buckshot and slugs.

Police have not said who purchased the gun. Two senior law enforcement officials previously told NBC News that the shooter’s mother bought it in August, around the time of his birthday.

“Bend Police detectives continue this complex investigation. They have served search warrants at the shooting suspect’s home, as well as on his electronic devices and his social media accounts on a variety of platforms,” police said in a statement Wednesday.

“That work continues, and it takes time,” the police department said.

Students in the greater Bend-La Pine Schools district returned to class Wednesday, although not at Silver Rail Elementary, where the shooting occurred.

“Through heartfelt artwork and messages of love, they are making sure every student who walks through the doors knows they are cared for, supported and loved,” the district said Tuesday as it prepared to welcome most students back.

Authorities have publicly identified two of the victims who were killed, 5-year-old Rhoam Summer and teacher Megan Lambert.

Drury, the wounded teacher, said in her statement that she heard a noise last week and went to investigate.

“Here is what I remember: Once I realized something was happening outside, I ran to see what was going on,” she said.

“I then saw the shooter and immediately ran back into the classroom. I turned to shut the door behind me, but the shooter was already there,” she said.

Drury said that there was nothing more she could have done and that “I was shot before I had any chance to act.”

“What happened in that classroom was unimaginable, and like so many in this community, my heart is broken for everyone affected by this tragedy,” she said.

“My thoughts are with those who were hurt, those we lost, their families, our school, and the Bend community,” she said. “I am truly grateful for the kindness and support we have received as we face the difficult days ahead together.”