An Arlington County sheriff's deputy is facing a first-degree murder charge in the death of 22-year-old Julian Dawkins.

Deputy Craig Patterson, a 17-year veteran with the sheriff's office, appeared in court via closed-circuit TV Friday. He was also charged with use of a firearm in committing a felony.

Investigators say Patterson, who was off-duty at the time, got into a dispute with Dawkins on the corner of Lynnhaven Drive and Evans Lane just after midnight May 22.

"As he left the scene, he was heard by a few witnesses to yell back at Dawkins that he would be back," Alexandria Commonwealth's Attorney Randy Sengel said.

Patterson then went home and returned to the scene of the argument with his gun, badge and handcuffs, prosecutors said.

At some point during the dispute, Dawkins was shot in the chest. Police said Patterson, 44, stayed on the scene and called 911. Dawkins was pronounced dead at an area hospital.

Sengel said Patterson falsely claimed he fired in self-defense on the 911 call. Patterson had claimed Dawkins threatened him with a knife, but police only found a folded pocketknife in Dawkins's pocket.

Prosecutors argued there was no way Dawkins could have presented the knife in a threatening manner given the way investigators found him.

News4's Shomari Stone spoke exclusively with Dawkins' mother, Gwen Prattmiller.

"There is nothing I'm not going to miss about my son," Prattmiller said. "He was all I had. I'm glad that they did finally charge the guy, but I still won't be at peace until I get a conviction out of the situation."

Prattmiller said she wants justice for her son, which she defined as life in jail without parole for Patterson.

Earlier this week, friends of Dawkins held a rally calling for Patterson's arrest.

"It's a great loss... to the family, the friends, the community," said family friend Patrick Cooper of Dawkins' death. "It's a great loss, and the way that it happened makes it even worse, just him being murdered by a police officer, you know. We're looking for some accountability."

Key witnesses stepped forward Wednesday, Alexandria Police Chief Earl Cook said.

"Witnesses that came forward provided us with enough evidence at this point to make the charge yesterday," he said.

An arrest warrant was issued for Patterson Thursday. He was later taken into custody and charged with murder.

Police hope more witnesses come forward.

Just hours after Patterson's court appearance Friday, a funeral was held for Dawkins. Antioch Church of Christ overflowed with mourners. Some told News4 they were relieved to learn of the arrest.

"It's good that they did get him, lock him up," said Lauren Bradford, who went to school with Dawkins. "That's what he needed to be from day one, in jail, but it's not gong to bring Julian back.

The area where Dawkins was shot was just four houses down from Dawkins' aunt's home, where the family was celebrating his cousin Tierra Ruffin-Pratt's contract with the WNBA's Washington Mystics.

Dawkins was a graduate of T.C. Williams High School and worked as a driver for PBS. The network's Gwen Ifill wrote that he "worked at the PBS NewsHour as a driver -- shuttling people, tapes and mail back and forth between our two office buildings with a bright smile for everyone."

Patterson has been placed on unpaid leave.

During Friday's court appearance, Patterson's public defender asked to be removed from the case due to a conflict of interest. He next appears in court on June 7, with his newly appointed private attorney.

Stay with NBCWashington.com for more on this developing story.

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