A Lorton man was certified to stand trial as an adult for allegedly shooting and killing his girlfriend’s parents as a 17-year-old in 2017, a case that generated national attention because he espoused neo-Nazi views.

A Fairfax County juvenile court judge also ruled Tuesday there was enough evidence to send the double-murder case against Nicholas Giampa, 19, to a grand jury in the county’s circuit court.

Giampa is accused of shooting Buckley Kuhn-Fricker, 43, and Scott Fricker, 48, inside their Reston home shortly before Christmas in 2017. Giampa had dated Kuhn-Fricker’s then-16-year-old daughter and attended class with her at a school for teens with emotional and learning issues. Police say Giampa then shot himself in the head.

The daughter, who is now 17, testified at Tuesday’s hearing about witnessing the shooting. Judge Kimberly J. Daniel excluded the media and public from the courtroom after prosecutors argued the publicity would be detrimental to her recovery after the incident.

Prosecutors did not offer a motive for the shooting Tuesday, but family and friends of Kuhn-Fricker said she staged an intervention to keep her daughter from seeing Giampa the week of the shootings, after discovering a Twitter account and messages tied to Giampa that showed a fascination with Nazis and espoused hatred of Jews, blacks and gays.

“I would feel a little bad reporting him if his online access was to basically be a normal teen, but he is a monster, and I have no pity for people like that,” Kuhn-Fricker wrote in an email to the principal of her daughter’s school five days before she was killed. “He made these choices. He is spreading hate.”

Giampa’s attorneys did not offer a defense in court and declined to comment after the hearing. Members of Giampa’s family said in interviews with The Washington Post last year that they did not believe he was a racist, that instead he posted the tweets to get a rise out of people online. They said he suffered from autism and depression and had few friends. They said he told them Kuhn-Fricker’s daughter had issues with her family and said they believe the killing stemmed from those issues, not from any white-supremacist beliefs.

“I wish it would have been us, not them,” Giampa’s mother previously said of the Frickers. “They truly didn’t deserve it. It comes back on me.”

Fairfax County police detective Kevin Reynolds testified Tuesday about arriving on the scene in the early hours of Dec. 22, 2017, as events were still unfolding. Giampa sat nearby in a green jail jumpsuit listening impassively. A long scar snaked across the side of his head and curled behind his ear from surgeries related to his gunshot wound.

Reynolds said authorities received a 911 call from the Fricker’s young son, saying both of his parents had been shot.

Janet Kuhn, Kuhn-Fricker’s mother, told The Post in 2017 that detectives told her that her daughter and son-in-law went to check on her granddaughter shortly before 5 a.m. after possibly hearing a sound.

The parents discovered Giampa in the daughter’s bedroom, Kuhn said detectives told her. Scott Fricker yelled at the boyfriend to get out of the house, but Giampa pulled out a gun and shot both parents, according to the account provided by detectives.

At Tuesday’s hearing, Reynolds testified that Fairfax County police officers made their way into the home soon after. The officers heard screaming from the upper floor and took to the stairs, Reynolds testified. Buckley Kuhn-Fricker was lying at the top, suffering from a gunshot wound. She appeared dead.

Reynolds told the courtroom he heard a gunshot coming from a room with a closed door. The Frickers’ daughter soon exited, saying, “He shot himself,” Reynolds testified.

Reynolds said he entered the room and found Giampa writhing on the floor. “It looked like he had a gunshot wound to the forehead,” Reynolds testified.

Scott Fricker was found suffering from a gunshot wound in another room. Both Frickers were pronounced dead at the scene. Giampa was taken to a hospital and underwent months of treatment and surgeries.

Janet Kuhn has said the events were set in motion earlier that week. Kuhn-Fricker, who owned an elder-care business and had a law degree, sent the email to the principal at the Dominion School laying out her concerns about Giampa on the Sunday before the killings.

Kuhn-Fricker discovered Giampa’s Twitter account, which has since been deleted, while looking at her daughter’s phone. The account featured tweets praising Adolf Hitler, supporting Nazi book burnings, calling for “white revolution,” making derogatory comments about Jews and featuring an illustration of a man hanging from a noose beneath a slur for gay people. The tweets also featured Atomwaffen, a white-nationalist group whose members have been tied to a handful of killings.

Kuhn-Fricker wrote in the email to the principal that their daughter told her over the previous summer that the boyfriend was very good at history and that her daughter asked, “Did you know that Jews are partly to blame for World War II?”

On Wednesday of that week, Kuhn-Fricker spent the day pleading with her daughter to stop seeing Giampa because of his views and the relationship was broken off, friends and family said. By Thursday, the mother texted a friend saying the “outspoken Neo Nazi” was out of their lives.

Giampa’s family said the news sent him into a tailspin. He grew increasingly agitated and inconsolable. The teen wrote in a therapy workbook: “I’ve given up on trying to be happy. Everything I care about leaves or is taken away.”

Two days later, police said, he opened fire on the Frickers.