WARNING – DISTRESSING CONTENT: The Georgia man who filmed a video of Ahmaud Arbery's fatal shooting on a mobile phone was arrested on Thursday (local time) and charged with murder.
The Georgia Bureau of Investigation said 50-year-old William "Roddie" Bryan was arrested on charges of felony murder and criminal attempt to commit false imprisonment.
No other details were given.
The GBI said in a statement that it would hold a news conference on Friday morning (local time).
Arbery was slain on February 23 when a white father and son armed themselves and pursued him after spotting the 25-year-old black man running in their neighbourhood.
More than two months passed before authorities arrested Gregory McMichael, 64, and his son, Travis McMichael, 34, on charges of felony murder and aggravated assault.
Gregory McMichael told police he suspected Arbery was a burglar and that Arbery attacked his son before being shot.
Bryan lives in the same subdivision just outside the port city of Brunswick, and the video he took from the cab of his vehicle helped stir a national outcry when it leaked online.
Bryan's attorney, Kevin Gough, did not immediately return a phone message on Thursday.
He has previously insisted Bryan played no role in Arbery's death.
"Roddie Bryan is not now, and has never been, more than a witness to the shooting," Gough said in a statement on the case Monday.
"He is not a vigilante. Roddie did not participate in the horrific killing of this young man. Mr Bryan has committed no crime, and bears no criminal responsibility in the death of Ahmaud Arbery."
Bryan's video of the shooting was taken from the driver seat of a vehicle following behind Arbery as he runs along a residential street.
A pickup truck is parked in the road ahead of Arbery, with one man in the truck's bed and another standing beside the open driver's side door.
The video shows Arbery run around the truck to the right before he cuts back in front of it. Then a gunshot can be heard, followed by a second shot.
Arbery can be seen punching a man holding what appears to be a shotgun, who then fires a third shot point-blank.
Arbery staggers and falls face down in the street.
Gregory McMichael retired last year after more than two decades as an investigator for the local prosecutor's office.
Because of those ties, Brunswick Judicial Circuit District Attorney Jackie Johnson recused herself from the case.
Two outside prosecutors assigned the case have also stepped aside.
The McMichaels weren't arrested until May 7, after the Georgia Bureau of Investigation took over the shooting investigation from Glynn County police.
Soon after the GBI's involvement was announced, a Brunswick attorney with access to the shooting video released it to a local radio station — and copies soon proliferated online.
The McMichaels remain jailed in Glynn County waiting for a preliminary court hearing and for a judge to decide whether to free them on bond pending trial.
Lawyers for the father and son have urged people not to rush to judgment in the case.
Do you have a story tip? Email: firstname.lastname@example.org.