ATLANTA - When the TV ad appeared featuring a grief-stricken mother urging the public not to vote for a state attorney general candidate, the Georgia primary season took a sharp turn.

Even in a state known for tough political ads, the spot was eye-catching. And risky.

With less than a week before the state primary, the bare-knuckles race for attorney general has managed to make the battle for governor appear almost tame in comparison.

Kenneth Walker's mother, Emily, is featured in the 30-second spot for Cobb Democratic state Rep. Rob Teilhet, criticizing his opponent Ken Hodges for failing to secure a grand jury indictment against the deputy who shot and killed her unarmed son in a case that exposed racial tensions in west Georgia.

"He was lying on the ground unarmed when a police officer shot him twice in the head," Emily Walker says in the ad, which began airing last week. "But the officer got off because the prosecutor, Ken Hodges, forgot to swear him in, tried to hide the video and then refused to reopen the case. I could never get an answer why."

The advertisement has put Hodges on the defensive ahead of the July 20 primary, forcing him to answer questions about the handling of the Walker case.

"The death of Kenneth Walker was a tragedy, and my heart continues to be with the family," Hodges said during Sunday's candidate debate. "The fact that my opponent wants to exploit the family's grief and use it for political purposes is, quite frankly, disgusting."

With the first open attorney general seat in more than 60 years, Democrats and Republicans have been battling to make it to the general election in November.

Hodges and Teilhet have been fierce rivals. Even before the Walker ad lit up the airwaves, the two traded accusations over endorsements and experience. Teilhet has defended the ad, saying Hodges is running on his experience and the Walker case is an important part of Hodges' record.

"Mr. Hodges' campaign is almost completely based on his experience as a prosecutor," Teilhet said at Sunday's debate. "Any discussion of that experience must include a discussion of the Walker case."

Observers say the ad is likely the biggest bombshell yet this political season, though it's effect remains to be seen.

"It's definitely hard-hitting - it sort of floors you when you see it," said Kerwin Swint, a Kennesaw State University political science professor who wrote a book on negative campaigning.

Swint said some voters will be put off by the ad, but it could resonate with others.

"Some will say it's inappropriate and that they shouldn't have gone there," Swint said. "But the ad itself is well done enough that it could have the impact that Teilhet wanted to raise questions about Hodges and his tenure as district attorney."

Walker was pulled over in December 2003 after officers said they watched him leave a home that was staked out during a drug investigation. Video shows Muscogee County sheriff's deputy David Glisson shooting Walker in the head, killing him. No drugs or firearms were found in the vehicle or on any of its occupants.

Hodges, a former Dougherty County district attorney, was appointed the special prosecutor to present the case to the Muscogee County grand jury in November 2004. The panel decided not to indict Glisson, stirring racial tensions in Columbus because Walker was black and the deputy is white.

Hodges and his supporters have worked to discount Teilhet's claims.

Greg Edwards, who was Hodges' co-counsel in the Walker case, said Hodges never tried to hide the video and has repeatedly said he would bring the case back to a grand jury if there was new evidence.

The case did prompt Georgia lawmakers to pass legislation this year requiring prosecutors to swear in all witnesses who testify in front of grand juries.

"Should (the deputy) have been sworn in? Yes. Did it impact the case? Absolutely not," Hodges said. "Do I wish he had been sworn? Yes, for the simple fact that we wouldn't have this distraction."

The ad has gained the attention of voters like James Williams, a 42-year-old manager at an IT security company who called it "devastating."

"Whether it's accurate or not, Teilhet's ad shows Ken Hodges as someone who didn't do his job very well and the result was he caused a grieving mother more pain," said Williams.

On the Republican side, former U.S. Attorney Max Wood and state Sen. Preston Smith have taken turns targeting former Cobb County Commission chair Sam Olens, who has more money in his campaign coffers than both his opponents combined.

Smith has played up his Georgia roots and tried to cast Olens as an outsider.

"I'm a lifelong Republican and I'm a seventh-generation Georgian," Smith said at a debate Sunday. "You moved here from New Jersey, and you were a party official in the Democratic Party."

Wood has criticized Olens for allowing an atheist to deliver the opening invocation at Cobb County commission meetings. And he has questioned contributions from Olens supporters who have donated to other Democratic campaigns and voted in Democratic contests.

Olens hasn't tried to distance himself from his Democratic supporters.

"If we want to take back the attorney general's office this November, we better have both Republican and Democrat support," he said.