A brutal beating; a terrible murder. Seeking motives in a divided America.

What’s going on, Daddy?” asked my 6-year-old son.

It was the morning of Nov. 12, a Saturday — or “Dadurday” at my house — and we were in my pickup truck, headed to a family outing.

 But now, about five minutes from our home in El Sobrante, California, our progress had halted: yellow plastic crime scene tape stretched across the road, blocking all traffic. I saw no signs of a car crash — no twisted and deformed automobiles, no skid marks streaking across the pavement, no piles of broken glass. What I did see were a whole lot of sheriff’s deputies standing around looking very grim. I’ve been a journalist for many years. I’ve reported on enough crimes to have recurring nightmares. My guess was that someone had been murdered.

What do you say when someone has been killed in front of your local library?

Me, I said nothing. “I don’t know, son,” I replied, as I wheeled the truck around.

Days later, authorities made an announcement about the crime: Three men had beaten, robbed and shot William Sims, a 28-year-old African American, leaving his body in the roadway, the sheriff’s department alleged. The killing was at least partially motivated by racism, according to prosecutors, who filed hate-crime charges.

I started my job as a reporter with ProPublica by covering hate crimes in New Orleans eight years ago. Now I’m back on the beat. And the stories are in my backyard — and all across the rest of the nation.

A wave of ugly incidents has washed over the country in the weeks since Donald J. Trump was elected; one watchdog group, the Southern Poverty Law Center, counted some 867 episodes of hate and intimidation in the 10 days following the election. Many were clearly fueled by politics — the graffiti in Wellsville, New York (“Make America White Again” next to a massive swastika), the man in Chicago who called a Muslim woman a “sand-nigger” before adding, “Thank God Trump is now president. He’s gonna deport your terrorist ass.”

The aggression has flowed in both directions: There have also been at least two dozen reported attacks on Trump supporters.

Sims was murdered just a few days after Trump’s victory at the polls. In my community, I heard many questions: Was the slaying a random crime? What role, if any, did race play in the incident? Was this the sort of politically inspired crime we’ve seen in so many other places, the types of episodes I’ll be exploring in the years to come?

A few weeks later, I was at the county courthouse in Richmond, not far from El Sobrante. It’s a dismal building. Think “Better Call Saul.” I was sitting in the back of a small courtroom with low ceilings, harsh fluorescent lights, and, on one side, a cage made of metal bars and thick sheets of bulletproof polycarbonate plastic. Clad in yellow sweatshirts, inmates stared out at the judge from the cage.

I was there to witness the arraignment of Chase Little and Colton Tye LeBlanc, two white men accused of attacking an adherent of the Sikh faith in a roadway altercation.

The episode had attracted national media coverage when it occurred back in September, just before the first the debate between Trump and Hillary Clinton. It seems to have started at a stop light in Richmond. Little and LeBlanc were with three or four other guys in a Ford F-150 pickup truck, while Maan Singh Khalsa, who is of Indian descent, was in the next lane over in a sedan. Somebody in the truck chucked a beer can at Khalsa, a 41-year-old IT specialist and caregiver to the elderly. Unpleasantries were exchanged.

Then, allegedly, Little and LeBlanc attacked Khalsa, pulling the man’s head through the window of his car, punching him in the face until his teeth came loose, damaging his eye, and, at some point, yanking off his turban and hacking at his long dark hair with a knife. Reportedly one of the men yelled, “Cut off his [expletive] hair!” during the attack. In the course of the assault, Khalsa injured a finger, which later grew infected, turned black and necrotic, and had to be amputated.

For followers of Sikhism, which is entirely distinct from Islam or Hinduism, hair is sacred, an article of faith. The gurus who founded the religion some 500 years ago in the Punjab region of South Asia directed male followers to keep their locks unshorn as a symbol of living humbly and in harmony with God; the turban was to be worn as a sign of piety and commitment to the faith.  As the Sikh Coalition, a national civil-rights group, put it in a letter to the county prosecutor, “When a Sikh ties a turban, the turban ceases to be just a piece of cloth and becomes one and the same with the Sikh’s head. It is a religious commitment without which the believer ceases to be a Sikh.”

When I read about the incident in the local news, I was stunned. The crime had occurred just a few miles from my home.

As I learned more about the case, I found out that LeBlanc and Little weren’t from anywhere near California. They were from Texas. They had come to our state to work a short-term gig at the Chevron Refinery in Richmond.

By the time LeBlanc and Little were formally arraigned, the media had largely forgotten about the attack. There was only one other reporter in the courtroom as the men stood and faced the judge.

Outside the courtroom, I approached the men. LeBlanc, 24, was in a brown plaid western shirt, his face framed by a cascade of sandy-blond hair hanging down past his shoulders. Little, 31, looked depressed as he stuffed his hands into the pockets of his fancy jeans. He was wearing cowboy boots.

I had so many questions. Over and over Trump had portrayed immigrants as a profound threat to the existence of the republic, an incoming swarm of criminals and job-stealers and terrorists. Had Little and LeBlanc heard these statements? Had they taken them as an entreaty to violence?

Both defendants were courteous. But neither was eager to talk. They had been charged with “assault by means likely to produce great bodily injury” and assault with a deadly weapon (the knife), charges prosecutors had augmented by adding special hate-crime enhancements. Both were facing potential prison sentences.

Later, LeBlanc’s attorney, Joseph Tully, emailed me a statement: “There is no evidence that this was a ‘hate crime’ as suggested by the State. In the alleged victim’s statement to the police, he did not report facts or opinion that the actions had anything to do with hate, i.e. related to ethnicity or belief. This was simply a fight over a beer can at a stop light which can’t be elevated to a hate crime under any circumstance.”

Khalsa, continued Tully, had become outraged and aggressive when his car was pelted with the can — and now he was using current concerns about hate crimes in the age of Trump as “cover” for his own bad behavior.

The Sikh Coalition, which has examined the matter closely, strongly disputed that characterization of events. “The violent assault and desecration of Mr. Khalsa’s religious articles of faith were motivated by clear bias and fit the definition of a hate crime,” said Harsimran Kaur, the coalition’s legal director. “This bias was reported to police immediately and we have confidence that the legal system will clearly see the facts for what they are.”

Khalsa declined to speak to the media while the case was moving through the courts.

My son wanted to know where I was going. “I gotta work, buddy, sorry,” I told him.

It was Dec. 3 — another Saturday — and there was a vigil for William Sims at the site where he died, in front of the library. In life, Sims had been known for his musical talent — violin, saxophone, piano, guitar, voice. Now, in death, he was becoming known as the guy who got killed by three racists.

For many in the crowd there was a sense that something profound had changed in American life, that Sims, and Khalsa before him, were victims of a new viciousness. “There’s a lot of anxiety, a lot of fear,” said Satinder Singh Malhi, a Sikh who attends the local gurdwara, or temple, and had come to the vigil with his family. “Basically we had a presidential candidate, now our president, who has given people license to express their prejudices.”

The exact motives for the killing, though, remained murky. A lawyer for one of the accused told the local media his client wasn’t a racist and didn’t have “a hateful bone in his body.” Mark Peterson, the Contra Costa County District Attorney, had said little publicly about the case.

“I don’t know the whole story,” Nancy Burke, an El Sobrante business owner, told me as we spoke in front of a makeshift memorial to Sims. “I don’t think anybody does.”

I went home and wrapped my arms around my squirmy little boy and pulled him close for a few moments.

I didn’t know what else to do.