CHAPEL HILL, North Carolina — A 46-year-old man has been charged with murder in the shooting deaths of three students in an apartment near the University of North Carolina at Chapel Hill campus. Police said “an ongoing neighbor dispute over parking” may have been a factor in the shootings Tuesday evening. The suspect, Craig Stephen Hicks, turned himself in to police later in the night and is being held in the Durham County Jail without bond. He was cooperating with investigators, police said Wednesday morning.

“Our investigators are exploring what could have motivated Mr. Hicks to commit such a senseless and tragic act. We understand the concerns about the possibility that this was hate-motivated and we will exhaust every lead to determine if that is the case,” said Chapel Hill Police Chief Chris Blue.

But given the victims’ religion — they were Muslims — and comments the alleged shooter apparently left on a Facebook page, many social media users wondered what role, if any, the victims’ faith played. The victims were Deah Shaddy Barakat, 23, Yusor Mohammad, 21, and Razan Mohammad Abu-Salha, 19. Barakat was Mohammad’s husband; Abu-Salha was her sister, the school said.

Barakat was a second-year student at the UNC School of Dentistry, who was raising money on a fundraising site to provide dental care to Syrian refugees in Turkey. He had been married for just over a month to Yusor Mohammad, who was planning to begin her dental studies at UNC in the fall, according to the school. Abu-Salha was a student at North Carolina State University in Raleigh.

All three were shot in the head, sources told CNN affiliate WRAL. The condominium is home to many university students. Tuesday night, friends and family members gathered, crying or comforting each other, as they waited for word from officers.

“It’s been hours. Just tell me if he’s alive,” one man cried out. An officer tried to calm him down. “Give us more time,” he said.

Student Kristen Boling told CNN affiliate WNCN she was at home studying and didn’t hear anything.

“It’s kind of just turned the neighborhood upside down,” she said.

The hashtag #chapelhillshooting and #MuslimLivesMatter quickly shot to the top of Twitter’s trending topic early Wednesday morning, with many posting what they said were photos of the victims.

Hicks is being held on three counts of first-degree murder. In one post widely shared online, Hicks, who claimed he is an atheist, allegedly wrote: “When it comes to insults, your religion started this, not me. If your religion kept its big mouth shut, so would I.”

CNN couldn’t independently confirm the authenticity of the post or his Facebook page.

UNC Chancellor Carol Folt is expected to issue a statement sometime Wednesday.

“We are sensitive to the impact an incident of this nature has on campus and in the community,” the school said. “We understand you want to know the facts as quickly as possible. At the same time, we must respect the job our Chapel Hill police have as they investigate this crime.”

CNN’s Tina Burnside, Rick Martin and Melodi Smith contributed to this report.