A St. Paul man who posed as a gun collector and sold large quantities of weapons online, some of which surfaced at crime scenes in the Twin Cities, will serve 18 months in prison.

The case against Eitan B. Feldman, filed in February, was among the first charged in the wake of President Obama’s pledge to crack down on unregulated firearms sales.

“Feldman’s actions in this case put firearms in the hands of criminals in the Twin Cities and jeopardized public safety,” said James Modzelewski, special agent in charge of the St. Paul field division for the federal Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). “[The] ATF is committed to working with local police and prosecutors to identify illegal sources of firearms, and hold them accountable. If we’re going to impact gun violence in our communities, we all need to work together to prevent criminals from getting guns.”

Feldman’s attorney, Joseph Tamburino, said his client didn’t know he was breaking the law when he first started making sales, but that he did “the dumbest thing” when he continued with the transactions after law enforcement warned him to cease.

As for the sentence, Tamburino said Feldman “has no complaints about the system.”

At the time Feldman was indicted, his was only the third unlicensed-seller case charged by the U.S. attorney’s office in the past decade.

Assistant U.S. Attorney Benjamin Bejar, who prosecuted Feldman, said that “engaging in the business of unlicensed firearms sales ... circumvents the critical background check routinely performed by legitimate licensed firearms dealers.”

U.S. District Judge Patrick J. Schiltz’s sentencing in Minneapolis of Feldman, 30, who earlier pleaded guilty to one count of dealing firearms without a license, includes two years of supervised release after his prison time is complete.

The ATF found evidence linking Feldman’s sales to several handguns used in serious crimes.

The indictment said Feldman regularly bought firearms — mostly handguns — from licensed out-of-state sellers using an online auction site, had the weapons transferred to a Burnsville gun shop where he received them, and then quickly advertised them for sale on another website that facilitates gun sales without criminal background checks.

The allegations span two years, with Feldman’s last sale (of more than 50) coming in January at a shopping mall parking lot to an undercover officer used by the ATF.

His indictment came soon after Obama announced that the U.S. Department of Justice would toughen federal gun control efforts, including a warning that “a person can be [considered to be] engaged in the business of dealing in firearms” even if they conduct transactions only at gun shows or online. Those doing so, Obama said, must be licensed, just like dealers who run their businesses out of a traditional storefront.

Feldman advertised on Armslist.com to sell guns he had earlier bought from licensed dealers online. He first had the firearms transferred to L.E. Gun Sales in Burnsville, where he would receive them after completing required paperwork and submitting to a background check.