Suspect Arrested in Murder of Charlotte Protester The protester was fatally shot by a civilian at a protest Wednesday.

 -- Charlotte police have arrested a suspect in the murder of a protester at a demonstration this week.

The victim, Justin Carr, 26, was fatally shot by another civilian during Wednesday night's demonstrations over the police shooting on Tuesday of Keith Lamont Scott.

Charlotte-Mecklenburg Police Chief Kerr Putney said at a press conference Friday that video evidence led to the arrest that morning of a suspect in Carr's murder. The investigation is still ongoing.

"Just a tremendous amount of good detective work there," Putney said. "We already have established probable cause and have made that arrest."

Charlotte Mayor Jennifer Roberts said at the press conference that she believes police videos of the shooting "should be released," but it's a question of timing.

Chief Putney said he agreed that the police footage should be made public eventually, but releasing it too soon could undermine the investigation. He also said the probe into Scott's death has been officially handed over to North Carolina's State Bureau of Investigation, which will be in charge of providing updates and releasing further information.

The press conference followed a third night of protests over the police shooting of Scott, but Thursday night's protests were mostly peaceful.

The mayor of North Carolina's most populous city had signed an order for a curfew slated to go into effect at midnight.

But police later said the curfew would not be enforced as long as protests are peaceful -- and that was evident, as demonstrators remained in the streets well past midnight without any police intervention. Before 1 a.m., protesters were laying down in some streets, and marching in others.

The curfew was lifted at 6 a.m., per Mayor Roberts' order. The curfew is part of a proclamation of a state of emergency, that explains such a measure is necessary "in order to more effectively protect the lives and property of the people within the City of Charlotte."

Chanting "No Justice, No Peace" and "Don't Shoot, Hands Up," protesters began peacefully marching down streets around 7:30 p.m. Thursday -- surrounded by rifle-carrying National Guard officers -- carrying signs that read "End Police Terror," "Black Lives Matter," "I Hope I Don't Killed For Being Black" and "Black Power."

At 11:31 p.m., police tweeted that there were "no reports of officer or civilian injuries during tonight's demonstration," but half an hour later, police tweeted that two officers were being treated by EMS workers after they were sprayed with a chemical agent by demonstrators."

At a news conference the following morning, police said a National Guard officer was also treated for an injury suffered during the demonstrations.

Police said a total of three arrests during Thursday night's protests, with charges of failure to disperse, carrying concealed weapon and curfew violation.

The protest began around the same time that attorneys for Scott's family said they had watched police video of Scott's shooting, but were unable to ascertain if Scott indeed had a gun in his hands.

"After watching the videos, the family again has more questions than answers," a statement from the family's attorney's read. "When told by police to exit his vehicle, Mr. Scott did so in a very calm, non-aggressive manner. While police did give him several commands, he did not aggressively approach them or raise his hands at members of law enforcement at any time. It is impossible to discern from the videos what, if anything, Mr. Scott is holding in his hands."

At one point during the evening, protesters stopped to block an intersection near Bank of America's headquarters and chanted "release the tape," but when police and the National Guard moved in, protesters moved on.

Bank of America -- along with Wells Fargo and Duke Energy -- told its employees to stay out of Charlotte.

Protesters also descended upon I-277, as they did the previous two nights. Riot gear-wearing police managed to move protesters off I-277 after dispersing tear gas, according to WSOC. Pepper spray was also used.

This is story is developing. Please check back for updates.

ABC News' Darren Reynolds and Alexandra Faul contributed to this report.