By Mark Albright, Times Staff Writer
Published Wednesday, April 16, 2008 8:45 PM

Gun purchasers may want to dress appropriately at the 1,200 Wal-Mart stores that sell them firearms.

That's because later this year the discount store giant will start keeping a videotape record of each gun sale for comparison purposes with weapons and fake IDs police seize in crimes.

The retail giant volunteered to be lead retailer in a beefed-up national effort created by 60 mayors - 20 of them from Florida - led by New York City Mayor Michael Bloomberg to keep firearms from passing on to the wrong hands.

About 46 percent of all criminal gun trafficking investigations involve a legal purchaser who passes the weapon to someone not legally permitted to buy one, says the U.S . Bureau of Alcohol, Tobacco and Firearms.

The Mayors Against Illegal Guns coalition pledged to create a police database that will be live in each participating store to identify and trace sales.

Wal-Mart also agreed not to waive three day cooling-off requirements if a background check has not returned a result within three days ...