During his 18 years as municipal judge, Mike Martin said Riverdale police Maj. Greg ‘Lem’ Barney was a constant presence.

“Either serving as my bailiff … or testifying at multiple trials,” he said in a post on his public Facebook page. “He was the total professional.”

Martin said he was stunned to hear Barney was shot and killed Thursday “while he was simply doing his job.”

Clayton County police officers tried to serve a no-knock drug warrant about 11:15 a.m. at the Villages on the River, an apartment complex in the 6600 block of Church Street, Clayton police Chief Michael Register told The Atlanta Journal-Constitution.

The officer knocked on the suspect’s front door. Instead of surrendering, the suspect ran out a back door.

“He ran approximately 100 to 200 feet from the incident location and we had officers from Riverdale on the perimeter,” Register said. “He confronted one of the Riverdale officers and shot the officer in the torso.”

The suspect took off running toward the front of the apartment complex, where he was confronted and shot by a Clayton police officer, Register said.

Barney, who was not wearing a bulletproof vest, was taken to Southern Regional Medical Center, where doctors “worked vigorously to revive” him, Register said.

Just before 2:15 p.m., the chief, who was visibly shaken, announced the worst.

“Unfortunately,” Register said, “the Riverdale officer has succumbed to his injuries.”

He referred all questions about Barney to the Riverdale Police Department.

The suspect was taken to Atlanta Medical Center in critical condition, Clayton fire spokesman David Vasquez told Channel 2 Action News.

No Clayton officers were injured in the shooting, Register said.

However, “it’s a difficult time for everyone,” he said. “Anytime something like this happens, it’s just sad.”

The apartment complex was covered with officers from multiple agencies Thursday afternoon. The Georgia Bureau of Investigation was asked to look into the incident, which is normal protocol in officer-involved shootings.

Barney’s body is at GBI headquarters, where an autopsy will be performed Friday morning, agency spokesman Scott Dutton said.

Martin, the former longtime Riverdale municipal judge, said his thoughts and prayers were with Barney’s family.

“Clayton County law enforcement in general and the Riverdale Police Department in particular lost a good one today,” he said. “Rest in peace my friend.”

— Please return to AJC.com for updates.