Several U.S. senators, including the two from Connecticut, are urging gun dealers to crack down on gun sales that happen before background checks are completed.

Sens. Richard Blumenthal and Chris Murphy joined 11 other senators in urging dealers to stop selling firearms to people who do not first pass a background check.

They said that if a customer has a criminal record, the FBI tried to determine whether that person can legally own a gun.

Right now, if the process takes longer than 72 hours, the seller can complete the sale despite a heightened risk that the buyer could be a criminal.

The senators said that while WalMart does not allow these “default sales,” stores like Cabela’s, EZ Pawn and Bass Pro Shops do.

After the shooting deaths of church goers in Charleston, SC last month, the senators wrote a letter to the three country’s largest firearms dealers.

"The FBI acknowledges that a fully completed background check would have uncovered the alleged perpetrator's prior arrest on a drug charge and his drug addiction, thereby barring him from purchasing the .45-caliber handgun with which he took nine lives," the senators wrote. "In the last five years, the 'default to proceed' loophole has led gun retailers to proceed with 15,729 firearm sales to 'prohibited people' - individuals who were deemed ineligible to purchase a firearm once their background checks were completed."

The senators went on to say that the stores have a duty to ensure that their products do not get into the hands of dangerous people like 21-year-old Dylan Roof, the suspect in the Emanuel AME Church shooting.