A federal judge has ruled that data tracing the sales history of guns used in crimes must be released to the city, which hopes to use the information to bolster its civil case against the gun industry (search).

The city sought the data to help prove its argument that gun manufacturers use marketing and distribution practices that allow criminals to get firearms, creating a public nuisance.

Brooklyn federal Judge Cheryl Pollak ruled Wednesday that the city has the right to access the data, which tracks guns found during criminal investigations to the dealers where they were purchased, The New York Times reported Friday.

The data can be used to show that some dealers more frequently sell guns found in crimes than others.

The city's lead lawyer, Eric Proshansky, told the Times that the decision "is important to the city because the proof in these suits is developed by demonstrating through these databases that the gun industry knows about problems" in distribution networks.

The Justice Department, which fought the release of the data, argued that Attorney General John Ashcroft (search) changed a policy that had allowed the data to be released in certain situations.

Some law enforcement officials have said the release of the data could show which cases police are pursuing, potentially compromising criminal investigations.

The city's lawsuit against the gun industry, one of several filed by American cities, names 40 gun companies and distributors and is likely to go to trial this fall.