Arbery's killing, captured on a disturbing video, drew a national outcry. Gregory McMichael, 64, and his son Travis, 34, told police they chased Arbery because they thought he was a burglary suspect and acted in self-defense during a confrontation.
Two and a half months passed before they were charged with murder and aggravated assault, shortly after the state began investigating and a video of the shooting became public. Authorities say the third man charged in the case, 50-year-old William "Roddie" Bryan Jr., boxed Arbery in with his truck.
It was Bryan who filmed Arbery's death on his cellphone. An investigator later testified that Bryan said he heard Travis McMichael using a racial slur as Arbery lay dying.
Judge Timothy Walmsley accepted the not guilty pleas and waived arraignment at the request of the defense lawyers. No court date was immediately set.
Last month, Georgia Gov. Brian Kemp signed into law a landmark hate crime bill that gained momentum after Arbery's death. However, a local prosecutor said hate crime penalty enhancements are not an option in the case because the new law cannot be applied retroactively.
Erin Donahue contributed to this report.
This story was originally published by CBS News on July 17 at 12:24 p.m. ET.