In this story: Atlanta latest city to sue gun makers Negligent marketing RELATED STORIES, SITES

NEW YORK (CNN) -- Two men and nine women in Brooklyn failed to reach a verdict Thursday, their first day of deliberations in a groundbreaking case about whether gun makers can be held liable for gun violence.

Atlanta's Mayor Bill Campbell announced Thursday that the city had filed suit against 15 gun manufacturers and two trade associations

The federal jury asked to hear again the testimony from an agent of the U.S. Bureau of Alcohol, Tobacco and Firearms. The agent testified that handguns are fairly easy to obtain illegally at gun shows.

The jury is being asked to decide whether gun manufacturers should be held responsible for an oversupply of firearms. Families of seven shooting victims filed the lawsuit five years ago.

"We feel we've been victorious in just getting the case to trial," said Freddie Hamilton, plaintiff and mother of one of the victims.

Lawyers for gun manufacturers said in closing arguments Wednesday that their clients can't control the illegal flow of guns and can't stop criminals from pulling the trigger.

Atlanta filed suit against 15 gun manufacturers and two trade associations Thursday, joining four other U.S. cities in seeking damages for crime, deaths and injuries involving handgun use.

"Today we act to hold faceless companies accountable -- companies that create instruments of destruction -- for their failure to make products safer and to warn of their inherent dangers," Atlanta Mayor Bill Campbell told a news conference.

At the same time, the state Senate debated whether to bar Georgia cities from suing firearm manufacturers.

The bill before the state Legislature would prohibit Georgia cities and counties from bringing civil suits against gun manufacturers but affirm the state's right to file such lawsuits.

The case under deliberation in New York could encourage more cities across the country to sue gun makers if the plaintiffs win their argument of negligent marketing.

Lawyers for the families said gun makers are responsible because they sell huge numbers of guns in legal markets with lax gun laws. The attorneys contended those guns often wind up on the black market in other areas.

But gun makers denied that, saying the gun industry is strictly regulated. And, their lawyers argued, short of not making guns at all, gun makers could not have prevented the victims' deaths.

Reuters contributed to this report.

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