The witness who called Milton police to report a driver suspected of being impaired spoke out for the first time Thursday.

Channel 2's Mike Petchenik broke the story on Channel 2 Action News at 4 p.m. Tuesday about a grandmother accused of DUI with her grandson in the car.

Muriel Martin told Petchenik she saw the suspect, Cui Chen, 46, dazed and confused in the parking lot of a Walmart.

She called 911, and dispatchers in Alpharetta quickly sent police to avert what could have been a tragedy.

"Just doing what a citizen should do," Martin said.

Milton police said Martin did the right thing Saturday when she called 911 to report some strange behavior by a woman walking through a Milton Walmart parking lot with her 3-year-old grandson.

Petchenik obtained audio of the call through an open records request.

"She's going from car to car, and she seems dazed and confused," Martin said to the 911 operator.

Martin said she first saw Chen when the woman's grandson started hitting her own car with a shopping bag.

"I had got out of my car and said, 'Excuse me, your son just hit my car,' and she seemed completely disoriented and confused," Martin said.

Martin said Chen looked right through her.

"I didn't know if she was drunk, if she was sick, what had happened," Martin said.

Martin told Petchenik she saw Chen load the toddler into the front seat of the car, then drive off.

"Even as she was pulling out of the parking lot she would pull up, stop. Pull up, stop," Martin said.

Martin kept tabs on Chen, giving police her exact location.

"I'm just trying to make sure she's safe and the child is safe," Martin told the 911 operator.

Chen now faces DUI and child endangerment charges. Martin said she's thankful she intervened.

"That could have been a tragedy," she said.

Police took a blood test from Chen to determine whether she had alcohol or drugs in her system and are awaiting the results.

A family friend told Petchenik on Tuesday he believes she had low blood sugar from not eating.

Petchenik attempted to reach Chen again for comment Wednesday, but she didn't answer her door.

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