An Oklahoma man will be facing a first-degree murder charge in the shooting death of his 37-year-old neighbor, police said, and the family of the victim and one leading advocacy group have suggested that anti-Muslim sentiment could have played a role in the alleged attack.

Stanley "Vernon" Majors, 61, is accused of shooting his next-door neighbor, Khalid Jabara, Friday night, according to the Tulsa Police Department. After shooting Jabara, Majors allegedly pointed his gun at a witness and fled the scene toward his home. Officers located him hiding behind a tree at a library, police said.

Earlier that evening, police responded to a 911 call made by Jabara, but left the scene after they were "unable to locate any criminal activity," police said.

Police said that there had been "many calls to the area that involved Majors acting aggressively towards his neighbors." Majors is currently awaiting trial on an assault with a deadly weapon charge involving Khalid Jabara's mother, Haifa Jabara, stemming from 2015, according to police and the Tulsa District Attorney's Office. He was initially held without bond, but a judge allowed his release three months ago, according to CNN. Majors has pleaded not guilty in that case.

In a family statement, Khalid Jabara's sister, Victoria Jabara Williams, said Majors was someone they "continuously brought to law enforcement's attention." When Khalid Jabara called police the night of his death, he stated that Majors "had a gun" and "was scared for what might happen," Williams said.

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"My family lived in fear of this man and his hatred for years," she said, adding that he had 'a history of bigotry against' the family," she said.

"He repeatedly attacked our ethnicity and perceived religion, making racist comments," she continued.

Police said earlier that they have not been able to talk to Majors as he became ill and was transported to the hospital shortly after he was taken into police custody, "so it is difficult for us to determine a motive." However, they said they "have recovered one handgun and ... are not looking for any other suspects at this time." Majors has since been released from the hospital and is currently in jail, police said.

Police said Majors had a protective order against him "that stated that he was supposed to stay a certain number of feet away from the victim’s mother and household."

"The protective order was issued by the Tulsa County District Courts," police said. "The Tulsa Police Department does not determine who can live somewhere and who can’t. We would only take action if someone were to violate that protective order."

Majors has yet to be formally charged. It is not clear if he has obtained a lawyer, the Tulsa District Attorney's Office told ABC News.

The Jabara family released a statement Monday to WSB-TV's sister station Fox 23:

"On Friday night, our world was shattered when our brother, Khalid Jabara, was murdered on the front porch of our family home. The perpetrator was not unknown to us—he is our neighbor—someone whom we continuously brought to law enforcement's attention. He killed our brother while awaiting trial for running over our mother, resulting in a broken shoulder, collapsed lung, broken ankle, broken nose, head trauma, and fractured ribs amongst other injuries. Only 30 minutes prior to my brother's shooting, Khalid called the police stating this man had a gun and that he was scared for what might happen. The police came and told him there was nothing to be done. Minutes later, the suspect murdered our brother with four shots.

My family lived in fear of this man and his hatred for years. Yet in May, not even one year after he ran over our mother and despite our repeated protests, he was released from jail with no conditions on his bond—no ankle monitor, no drug/alcohol testing, nothing.

This suspect had a history of bigotry against our family. He repeatedly attacked our ethnicity and perceived religion, making racist comments. He often called us "dirty Arabs," "filthy Lebanese," "Aye-rabs," and "Mooslems"—a fact highlighted by the Tulsa Police Department who also heard these comments from the suspect. The suspect's bigotry was not isolated to us alone. He made xenophobic comments about many in our community -- "filthy Mexican" and the "n" word were all part of his hateful approach to anyone from a different background.

Today, in our pain, we are also keenly aware that this is not just another murder to be added to crime statistics. Our brother's death could have been prevented. This man was a known danger. He intentionally tried to kill our mother less than one year ago when he ran her over with his car. Based on his racist comments towards us, he should have been charged with a hate crime then. He should not have been released without monitoring. Yet he was released and put back next door to us, the family he assaulted just months before. This is troubling at any time, but profoundly disturbing given the current climate of our country and the increase nationally in cases of hate crimes.

Our brother Khalid was just 37 years old and had his whole life ahead of him. He was a kind spirit, loving brother, uncle and son. Khalid's heart was big. He cared for our entire family, our friends and people he didn't even know. He created every Jabara family joke and filled our lives with love and laughter. All of that has been taken away from us by this hateful man and a system that failed to protect our community."