In this Tuesday, Feb. 10, 2015 photo, Chapel Hill police officers investigate the scene of three murders near Summerwalk Circle in Chapel Hill, N.C. A man, his wife and her sister, all college students, were shot to death at a quiet condominium complex near the University of North Carolina, but police had not yet given a motive or released details about the suspect. Craig Stephen Hicks, 46, was charged with three counts of first-degree murder in the Tuesday shooting, Chapel Hill police told local news outlets.

Image Credit: (AP Photo/The News & Observer, Al Drago)

CHAPEL HILL, N.C. - A long-running parking dispute between neighbours motivated a man to kill a woman, her husband and her sister at a quiet condominium complex near the University of North Carolina campus, police said Wednesday.

Beyond the parking dispute, police didn't comment further on the motivation or details of the crime, but a Muslim civil rights and advocacy organization asked authorities to address speculation — much of it on social media — about possible anti-Muslim bias. The three victims were Muslim, a friend said.

Craig Stephen Hicks, 46, was charged with three counts of first-degree murder in Tuesday's shooting of Deah Shaddy Barakat, 23, Yusor Mohammad, 21, and Razan Mohammad Abu-Salha, 19.

Barakat and Mohammad were married, and Abu-Salha was Mohammad's sister.

Hicks appeared briefly in court Wednesday morning. He spoke only to answer that he understood the charges and to confirm an indigency affidavit. District Judge Marcia Morey said he would be appointed a public defender and held without bond until a March 4 hearing.

Police said Hicks was co-operating with the investigation and that their preliminary investigation showed that the parking dispute was the motive.

Hicks' wife, Karen Hicks, and a former roommate of Barakat confirmed that Craig Hicks had been part of a long-running parking dispute.

"I can say that it is my absolute belief that this incident had nothing up do with religion or the victims' faith, but in fact was related to long-standing parking disputes my husband had with various neighbours regardless of their race, religion or creed," Karen Hicks said.

One of her attorneys, Robert Maitland, said Hicks had tried to resolve the parking dispute with the homeowners association several times without success.

Imad Ahmad, who said he lived with Barakat for more than a year, said Hicks would knock on their door about once a month to complain the two men were parking in one of the spaces designated for visitors in addition to the one space reserved for each residence.

"He would come over to the door. Knock on the door and then have a gun on his hip saying you guys need to not park here," said Ahmad, 24, who said Hicks carried the handgun in a holster. "He did it again after they got married."

Another attorney for Karen Hicks, Michele English, said Craig Hicks had a concealed weapons permit.

But outrage spread among American Muslims who viewed the homicides as an outgrowth of anti-Muslim opinions in the U.S. Many posted social media updates with the Twitter hashtags #MuslimLivesMatter and #CallItTerrorism

"Based on the brutal nature of this crime ... the religious attire of two of the victims, and the rising anti-Muslim rhetoric in American society, we urge state and federal law enforcement authorities to quickly address speculation of a possible bias motive in this case," Nihad Awad, of the Council on American-Islamic Relations, said in a statement.

In an email, Chapel Hill police Chief Chris Blue said, "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."

Durham district attorney Roger Echols said he couldn't discuss a motive. Asked whether Hicks could be charged with a hate crime, he said the facts of the case were still under investigation.

U.S. Attorney Ripley Rand said his office was monitoring the investigation but that it was not yet a federal investigation. He said the shooting appeared to be "an isolated incident."

Gerod King of the Bureau of Alcohol, Tobacco, Firearms and Explosives said agents were in touch with the U.S. attorney's office and that investigators hadn't ruled out a hate crime.

Abdullah Antepli, director of Muslim affairs at nearby Duke University, issued a statement calling for people not to jump to conclusions over the motive for the killings.

Barakat's family was from Syria, and he was raising money to help refugees of the country's civil war, Mustafa said. Mohammad travelled to Turkey last summer to help treat dental problems in Syrian refugees in that country, Mustafa said.

News from © The Associated Press, 2015