DURHAM, N.C. — He hated religion. He hated rule breakers. He hated people who parked in his spot.

The man at the center of a case that caused a worldwide furor four years ago over anti-Muslim violence was filled with so much hate that he shot and killed three of his neighbors, all students of Middle Eastern descent, at his apartment complex in Chapel Hill, N.C.

The man, Craig Hicks, pleaded guilty on Wednesday and will serve three consecutive sentences of life without parole for murders that the police initially said stemmed from a parking dispute.

Even so, the case has tested the limitations of the legal system on the question of when a hateful crime becomes a hate crime. Across the country, reports of bias-based attacks are on the rise. But many such cases that get to court are not officially prosecuted as hate crimes, to the surprise and sometimes the dismay of those on the victims’ side, for whom the question can be as much a moral issue as a legal one.

The families of the slain students — Razan Mohammad Abu-Salha, 19; her sister, Yusor Mohammad Abu-Salha, 21; and Yusor’s new husband, Deah Shaddy Barakat, 23 — have repeatedly pressed for a hate crime designation, to no avail.

North Carolina does not have a hate crime statute that would apply to first-degree murder, but the family met repeatedly with the federal prosecutor, and then — twice — with his superior at the Justice Department.

“If a Muslim man knocked on a door and executed a Christian family in their home with no provocation, that would be called terrorism,” Dr. Mohammad Abu-Salha, the sisters’ father, said in frustration. “But we Muslims are soft targets.”

With Mr. Hicks’s guilt not in question and his sentence decided upon, the last few days have seen furious attempts to ensure that the record reflects the gravity of the crime.

In court and legal filings, Mr. Hicks, 50, has been called a white supremacist, a bigot and a monster. At the hearing, the Durham County district attorney, Satana Deberry, had an expert witness testify about the concept of implicit bias, or unconsciously held negative stereotypes. Implicit bias has been cited in police shootings of unarmed black men.

The expert, Samuel Sommers, a psychologist at Tufts University, said it was reasonable to assume that Mr. Hicks had acted out of “intergroup bias.”

The prosecution also played excerpts from a video of Mr. Hicks’s confession. In the recording, he giggles after saying that he had spent part of the morning playing Assassin’s Creed, a video game, and boasts of the accuracy of his gun. Mr. Hicks describes Mr. Barakat as full of profanity-laden defiance during the encounter.

But then, with the news media ordered to turn off recorders and cameras and the courtroom packed with families and friends of the victims, many in Muslim dress, the prosecutor played a video taken on Mr. Barakat’s phone during the shootings.

That video, never before made public, recorded what happened after Mr. Barakat opened the door to Mr. Hicks’s knock on Feb. 10, 2015. “You’ve got three cars in the lot, and I don’t have a parking spot,” Mr. Hicks is heard to say.

In the video, Mr. Barakat remains polite and does not curse. Mr. Hicks says, “If you’re going to be disrespectful towards me, I am going to be disrespectful of you.”

Asked to leave, Mr. Hicks pulls his gun and shoots Mr. Barakat from the porch. The two women can be heard shrieking and begging at the top of their lungs.

In the courtroom, some people cried out and prayed as the video of the massacre was played, or shouted out at Mr. Hicks, until the judge, Orlando Hudson, asked for calm.

None of the three students had parked in Mr. Hicks’s assigned spot, and only two had parked anywhere in the lot, according to police and court records.

Mr. Hicks’ story raised the question of whether he was inventing pretexts to explain his violence or believed his own story because, as Professor Sommers suggested in an affidavit, his perceptions were distorted by prejudice.

Hate crimes, in which victims are chosen because they belong to or are thought to belong to a particular group, are given a special status in law because they can leave an entire community of people feeling threatened and violated.

After the 2015 shootings, Dr. Abu-Salha said, his mosque added armed security at Friday prayer services, friends bought guns for self-defense and some Muslim women stopped wearing head scarves out of fear.

Mr. Hicks was an angry white man, unemployed, with few assets other than a small arsenal of firearms and a $2,000 car. He owed $14,000 in child support.

His social media posts were anti-religion, but did not single out a specific religion. He kept copious records of his obsession over violations of the parking rules at the complex and related confrontations, complaints and calls to towing services. He had once come knocking on the victims’ door, brandishing a gun, to complain about noise. They had been playing the board game Risk.

In a recent jailhouse interview he called the three students “disrespectful punks.”

He had not known the three were Muslims, he said, though the women always wore headscarves, and though Mr. Hicks went on to complain that he had seen them violating the Muslim duty to fast during Ramadan.

Experts said violence against people simply because they were religious could be considered a bias crime no matter what their faith was. But Mr. Hicks insisted religion had nothing to do with the murders.

“I’ve defended Muslims. I know Muslims,” he said. “I take pity on them, the way society treats them like they are lesser people.”

At a hearing last week, Mr. Hicks’s lawyers tried unsuccessfully to quash any testimony on implicit bias, saying that it was an untested body of social science and that there were no legal grounds for “punishing a person for his unconscious beliefs, for which he is by definition unaware.”

On Wednesday, Mr. Hicks’s lawyers asked no questions of Professor Sommers.

One reason that some bias crimes are not prosecuted under hate crime laws is that defendants like Mr. Hicks already face the steepest possible penalties, said Brian Levin, director of the Center for the Study of Hate and Extremism at California State University in San Bernardino.

In 2015, the Hicks case landed on the desk of Ripley Rand, then the United States attorney for the Middle District of North Carolina. In an interview this year, Mr. Rand said the federal government was meant to intervene if local authorities could not or would not do their jobs, which did not seem to be the case in Durham, where Mr. Hicks had seemed destined to spend the rest of his life in prison.

Mr. Rand said he had told the families back then that the blurred motives complicated the application of the hate crime law, and was surprised to learn that they were still waiting for public recognition that the murders were motivated by hate.

“I have failed the family in not making sure the family fully understood the law,” he said.

The family appealed to Vanita Gupta, then the assistant attorney general running the Justice Department’s Civil Rights Division, who met with them twice. Ms. Gupta declined to discuss the case but, speaking generally, explained that the department was governed by a Sixth Circuit decision that did not allow for mixed motives, setting what some experts said was a higher bar than the law requires.

“The proof must be very clear that the only motivation for the crime is hate,” Ms. Gupta said.

Legal standards, however, are not the same as moral standards. And that, Professor Levin said, is where the victim impact statements come in: as “the moral anchor for what we do next.”

Mr. Hicks had initially asked to be excused from the courtroom before the victims’ family members spoke. “I like to think I’ve got empathy, but I look at the way I act with stuff and really wonder if I do,” he said in an interview. “I feel sorry for the family members, but at the same time I really don’t want to deal with them, and that would be empathy.”

Dr. Abu-Salha objected, saying that letting Mr. Hicks be absent would be “coddling” him.

“In no just world,” he wrote in a letter to the court, “should he be able to murder children and not face the words of the families whose lives he has destroyed.”

After reading the letter, Mr. Hicks withdrew his request to leave the courtroom.

Courtesy of New York Times