NEWPORT, Oregon — The twisted Oregon šhσσtєr who killed three kids and a teacher at his old elementary school had an alcoholic father who beat the boy’s mother and threatened her with a knife before he was even born — forcing her to move across the state, according to court documents.

Griffin John was let out of prison early after he was sentenced to 48 months behind bars for the attack on wife Shauntai Nickerson — and he begged a judge to lift a restraining order against him so he could “see his son grow up” in the coastal town of Newport, docs obtained by The Post said.

Eight months later, Griffin J. John II was born — but his mother and father didn’t stay together long. Within months, Nickerson moved her son three hours west to Bend, Oregon.

Police say Griffin John II used his mom’s shotgun to blast his way through the door at Silver Rail Elementary in Bend last Thursday. He targeted his special education classroom, 𝘬iᩚlling 5-year-old Rhoam Summer, an 8-year-old and an 11-year-old, along with teacher Megan Lambert, 25.

A 7-year-old in a wheelchair was shot in the face and hospitalized, and a 54-year-old teacher was also wounded.

John, 16, was then killed by a heroic armed parent who confronted him in the school.

Back in their hometown in eastern Oregon, both the John and the Nickerson families have rough reputations.

The elder Griffin John revealed in letters to a judge after his domestic violence arrest that he had a history of alcohol 𝘢bu𝘴e and had been in jail “several times in the past.”

When he was let out early, he only stayed free for a few years.

He was arrested in 2012 for allegedly head-butting a cop in Newport, boozing and smoking pot in violation of his parole, according to court docs.

It’s unclear whether he was convicted in that case.

And his reputation around town jibed, as a bartender in Nickerson’s hometown of neighboring Toledo claimed he once made gross remarks to a teenage girl.

Neither John nor Nickerson could be reached for comment — and numerous family members refused to speak to The Post.

One threatened a reporter with dogs when The Post sought comment.

Here’s the latest on the elementary school śh́óóting in Oregon:

• Hero teacher who wrestled Oregon school šhσσtєr for gun speaks out for first time: ‘It all happened so fast’
• Disabled girl, 7, gravely injured during Oregon school śh́óóting moved out of ICU — as nearly $1.1M in donations pour in
• Hero dad who killed Oregon school šhσσtєr recalls hearing children ‘pleading for their lives’ as massacre unfolded
• Oregon šhσσtєr Griffin John developed sickening obsession before 𝘬iᩚlling 4 in school massacre

Nickerson did provide a brief comment to reporters the day after the śh́óóting, telling them, “I’m sorry … I miss him.”

She insisted he was “a good boy, he really was,” but she declined to say how he got her shotgun.

“If I could have prevented this, I would have,” she said.