While police are still investigating the motive behind Craig Hicks' decision to shoot and kill three Muslim college students in an apartment complex in Chapel Hill, NC, authorities have said the crime may have been motivated by an ongoing feud over parking—but a hate crime hasn't been ruled out.

In the days following the shooting of Deah Shaddy Barakat, his wife, Yusor Mohammad, and her sister, Razan Mohammad Abu-Salha, neighbors at the apartment complex where the couple and Hicks lived have come forward and told multiple outlets about Hicks' apparently confrontational fixation with parking spots and noise. He apparently knocked at the door of Deah Shaddy Barakat and Yusor Mohammad on more than one occasion to complain—with a gun holstered at his belt.

"This man had picked on my daughter and her husband a couple of times before, and he talked with them with his gun in his belt," the sisters' father, Dr. Mohammad Abu-Salha, told the New York Times. "They were uncomfortable with him, but they did not know he would go this far."

Yusor Abu-Salha's friend, Amira Ata, recalled such a story—of Hicks speaking to the couple at their front door with a gun in his belt—to Fusion:

In October or November, we went to dinner at Yusor and Deah's house. Right after we left, Yusor heard a knock at the door and it was Hicks. She told us he was angry and said we were noisy and there were two extra cars in the neighborhood. We used visitor parking but he was still mad. He said we woke up his wife. It wasn't that dark yet. It wasn't late. And it wasn't that loud. We were playing a board game called Risk. I mean, I know I was mad because they were beating me at the game, but that was it. While he was at the door talking to Yusor, he was holding a rifle, she told me later. He didn't point it at anyone, but he still had it. Yusor called to check on us after we left, to make sure he hadn't approached us. We thought that was so weird—our neighbors don't come to the door with guns! So when I heard the news it was shocking, but it wasn't a surprise that it was the neighbor.

And another neighbor, Samantha Maness, described Hicks to the Times as "definitely aggressive":

Ms. Maness said Mr. Hicks would often seek to have cars towed from the complex's lot, either because they did not have stickers or because he did not recognize them. And she said he would complain about noise — he was upset when she and her friends were playing a card game and he thought they were too noisy, and he was again upset when she pulled into the lot with music playing loudly in her car.

"He was aggressive toward a lot of people in the community," Maness told the Charlotte Observer. "He had equal opportunity anger toward a lot of the residents here."

He supposedly became such a nuisance, neighbors say, they had to hold a meeting about him. And Hicks was apparently so obsessed with the apartment complex's parking, a towing company stopped taking his calls.

"It was often more than the average person," Christopher Lafreniere, a driver for Barnes Towing, told WRAL. "It actually got to the point that he was not allowed to call a car in. If he called, we wouldn't go out."

Much has been made of Hicks' Facebook page, marked by atheistic messages and anti-religious sentiment; the New York Times notes that "his anger appeared to be aimed primarily at Christians."

Hicks' wife Karen maintains that her husband, whom she is seeking a divorce from, was not motivated by religious animus, that the crime was about "the mundane issue" of parking.

"He just believes that everyone is equal," Karen Hicks said at a press conference in Chapel Hill Thursday. "One of the things I do know about him is that he would often post on his Facebook page that he was for same-sex marriage, abortion, and race."

[Image via WRAL]