BROOKLYN - Officials say a New York City undercoverinvestigation at an Arizona gun show found that private sellersdidn't always require background checks of buyers. Theinvestigation came weeks after a Tucson shooting that killed sixpeople and injured 13 others.

Officials say the guns were sold even to undercoverinvestigators who told sellers they probably couldn't passbackground checks.

The operation was conducted as part of the Bloombergadministration's effort to crack down on illegal gun salesnationwide.

Bloomberg last week urged Congress to make sure the system forbackground checks on firearms purchases includes the names ofeveryone prohibited from buying weapons.