NEW YORK and PHOENIX -- Officials say a New York City undercover investigation at an Arizona gun show found that private sellers didn't always require background checks of buyers. The investigation came just weeks after a Tucson shooting that killed six people and injured 13 others.
New York Mayor Michael Bloomberg is scheduled to show an undercover video on Monday of illegal firearms sales at the Phoenix gun show last week.
The New York Times says the guns were sold even to undercover investigators who told sellers they probably couldn't pass background checks.
The operation was conducted as part of the Bloomberg administration's effort to crack down on illegal gun sales nationwide.
Bloomberg last week urged Congress to make sure the system for background checks on firearms purchases includes the names of everyone prohibited from buying weapons.