Atlanta police were mourning a fellow police officer who was struck by an alleged drunk driver and killed late Tuesday night.

Senior Police Officer Gail Thomas, a 15-year veteran of the force, was assisting another officer with a traffic accident on the Brookwood Interchange ramp from  I-75 southbound to I-85 northbound, and had just gotten out of her patrol car when she was hit,  APD Chief George Turner said.

The Zone 5 morning watch officer had just started her shift when she was hit. Thomas, 46, died at the scene.

The driver whose vehicle hit the officer, 22-year-old Chasity Jones of Stone Mountain, was charged with driving under the influence, homicide by vehicle, 1st degree and reckless driving, according to Atlanta police spokesman Carlos Campos.

According to police, Jones registered a .16 on a breath test administered at the scene, but refused consent for a blood alcohol reading. However, a search warrant was obtained and blood was retrieved at Grady Memorial Hospital.

Jones was booked into the Fulton County Jail and is expected to go before a judge Thursday morning, according to Tracy Flanagan, a spokeswoman for the jail.

Turner said the incident left the officer's colleagues shaken.

"As you can imagine, there are a lot of very raw nerves and emotions," he said. "We are very concerned about the family, and also about our family. We encourage our officers to depend on each other and to seek out help."

Officer Katie Riester, who lowered the flag outside Atlanta police headquarters to half-staff Wednesday morning, remembered her fallen colleague as a “great police officer” who “loved policing.”

“She will be so missed by everyone here,” Riester said.

“She was such a sweet person,” Riester said. “Her smile was just infectious; she could just brighten up a room.”

Former Atlanta police Major John Woodard, who once supervised Thomas, agreed, telling the AJC in an e-mail that the officer "always had a smile on her face."

"Gail was one of the nicest people that you would ever want to meet," Woodard said. "Her death will leave a hole in the hearts of those who knew her."

Mayor Kasim Reed called Thomas a "veteran police officer whose sense of duty and commitment to public safety inspired many of her fellow officers."

Please return for updates.

Dispatch Editor Angel K. Brooks contributed to this article.