POWAY, California—Nineteen-year-old nursing student John T. Earnest, who was charged with murder Sunday as the lone gunman in the deadly Poway Synagogue shooting, played piano for hours a day and earned a 4.31 grade point average. His father was a church elder whom neighbors called “the sweetest man.”

But somewhere on his path, Earnest took a terrible turn, claiming Adolf Hitler as an idol and writing what appears to be his own rambling manifesto that Jews “deserved nothing but hell.” He wanted to be the one to, as he put it, “Send. Them. There.”

Police say someone purporting to be him posted the anti-Semitic, Islamophobic, white supremacist “manifesto”—which eerily mirrored the Q&A style that Christchurch terrorist Brenton Tarrant used in his own pre-massacre diatribe—about 20 minutes before he walked into the Poway synagogue with an AR-15 style assault rifle and started shooting—killing one woman and injuring three others—before the gun malfunctioned and he was chased out by an armed security guard.

Earnest was arrested by police a few minutes after the shooting as he fled, called 911, and told them where to find him off an exit on a California highway, authorities said. As an officer approached, he exited his vehicle, raised his hands, and surrendered. A rifle was recovered from the car. He is scheduled to be arraigned on Wednesday on one count of first-degree murder and three counts of attempted first-degree murder, according to the San Diego County Sheriff’s Department.

In his online posting, Earnest championed the likes of Robert Bowers, who fatally shot 11 people at the Tree of Life synagogue shootings in Pittsburgh six months ago, Tarrant, who killed 50 people in a New Zealand mosque in March; and Hitler.

He used mainstream social media like Twitter and the fringe message boards 8Chan in what has become a proven way for terrorist groups and lone wolves alike to ensure that propaganda is disseminated to both those looking for it and those who are not. He posted the original screed on Pastebin.com and Mediafire.com, and linked to them on 8Chan. Like Tarrant, he promised to live-stream his killing spree, which he evidently failed to pull off. Facebook immediately removed the profile link he intended to use, but had somehow not seen the warning signs when he created the page.

Sheriff William Gore of the San Diego County Sheriff’s Department said during a press conference late Sunday that authorities were carrying out searches in the suspect’s home and “looking into digital evidence and checking the authenticity of an online manifesto.”

If it is validated as authentic, the student, who was previously unknown to police, found footing in the usual tenets of hate and the now all-too-familiar desire for infamy.

Zach Keele, pastor of the Orthodox Presbyterian Church, where Earnest’s father was an elder, or officer of the church, confirmed that he was part of the parish. “So John T. Earnest is a member here,” he told The Daily Beast. “We completely deplore what he did. That is not part of our practices, our teachings in any way. Our hearts, our prayers, our tears go out to the victims, to all those wonderful neighbors at the synagogue.”

Keele said Earnest had never appeared to be the sort of person who would carry out this sort of an attack. “This is a complete surprise,” he said.

In a service at the church on Sunday, Keele delivered a sermon on betrayal and forgiveness, offering condolences to the victims–but also to Earnest’s family.

“We pray, Lord, for those who are hurting, and we pray for the victims of that synagogue,” Keele told the crowd of 50 or so parishioners. “We deeply mourn that this evil came out from us. We do not understand it, oh Lord, and we pray that you would forgive us for any such shortcoming, for any good deeds we left undone. We pray, Lord, that you will be with the Earnest family.”

Speaking to his congregation after the service, Keele said he had spoken with Earnest’s parents the night before. They had spent the night huddled in their other son’s apartment close to the beach while their own house was searched by SWAT teams, he said. Earnest’s father plans to release a statement Monday morning through an attorney. “It’s a good statement,” Keele said. “They have good family support.”

The minister added that Earnest must “suffer the full punishment of the law.” Still, he hopes he will “recant his hatred.” Keele plans to visit the young man in prison, if convicted, he said.

After the service, Gerrit Groenewold, a board member at the Orthodox Presbyterian Church who happens to be the father of the girlfriend of one of Earnest’s brothers, told The Daily Beast that he had noticed Earnest had seemed quiet, and often tried to reach out to the young man, but with little luck. “I have tried to talk to John several times, but he is very silent and very reclusive. I noticed that he was quiet and just wanted to have contact... The other [members of his family] are not nearly as quiet,” he said. “It’s not good if someone is that quiet. He needs to be part of the community, to let them know what is going on.”

Earnest also claimed responsibility for an attempted arson attack last month on Dar-ul-Arqam Mosque in Escondido, about nine miles from Poway, Security cameras at the mosque caught a suspect breaking a lock and pouring liquid on a side door but had failed to identify the person. Gore said investigators are now looking his “possible involvement in the arson and vandalism of mosque.”

In a comment that was left after the synagogue shooting, someone asks, “How does a child of such privilege go so horribly wrong? Where does this hatred come from?”

Late Saturday afternoon, California State University San Marcos president Karen S. Haynes confirmed that Earnest had been enrolled at the its nursing school.

“We are dismayed and disheartened that the alleged shooter—now in custody—is a CSUSM student. CSUSM is working collaboratively with the San Diego County Sheriff’s Department to assist and gain more information,” Haynes said in a statement. “We are heartbroken by this tragedy, which was motivated by hate and anti-Semitism.”

A man who identified himself as Earnest’s grandfather expressed shock at his grandson’s role in the deadly shooting on Saturday.

“He did what?” the man told The Daily Beast when reached by phone. “That is out of whack. My heart is sinking into my chest. I’m going to hang up now.”

By Saturday evening, police had barricaded the streets leading to the cul-de-sac in Rancho Peñasquitos, a hilly, middle-class suburb of San Diego about seven miles from the synagogue where Earnest lives with his family. More than three dozen law enforcement officers, including FBI agents, ATF agents, and cops, were at the scene. Eyewitnesses told The Daily Beast that the family left their home under police escort hours earlier.

Around 9 p.m. local time, law enforcement had secured a search warrant to enter Earnest’s house, which may well confirm the authenticity of his hate-filled screed and could possibly uncover how far he was willing to act on his hate.