LOUISVILLE, Ky. (AP) — The family of a man who opened fire at a Louisville bank is working to destroy the AR-15 rifle he used to kill five of his co-workers.

A state law in Kentucky sends firearms confiscated by law enforcement to auction, and the proceeds are used to buy law enforcement equipment. Last week after the shooting, Louisville Mayor Craig Greenberg said the “murder weapon will be back on the streets one day under Kentucky’s current law.”

Greenberg, who was shot at by an assailant during his mayoral campaign last year, has been critical of the law and has sought workarounds that would render crime weapons unusable after they are confiscated by his police force in Louisville.

The family of 25-year-old Connor Sturgeon, who lives in Indiana, said they were shocked to hear the gun he used in the April 10 attack could go back in circulation. Sturgeon was fatally shot by a responding police officer in the bank’s lobby.

“The Sturgeon family was aghast to learn Kentucky law mandated the assault rifle used in the horrific event last week be sold to the highest bidder at public auction,” according to a written statement released by a family spokesman Thursday.

The statement said the family is working “vigorously” to see that the rifle is destroyed. They said the first step in that process occurred April 17, when federal agents took possession of the rifle.

“This tragedy is yet another indication that meaningful, common sense gun safety measures must be enacted,” the statement said. “We respectfully urge the Kentucky state legislature to lead the way by changing Kentucky law to remove the gun auction provision.”

The confiscated guns are bought at auctions by federally licensed gun dealers. An auction held last year totaled nearly $174,000, according to Kentucky State Police.

One of the victims of the shooting, 63-year-old Tommy Elliott, was a friend of Greenberg’s and Kentucky Gov. Andy Beshear.

Eight other people were injured in the shooting at Old National Bank in the city’s downtown, including a rookie police officer who was shot in the head. Officer Nick Wilt remained in critical condition this week, and he was battling pneumonia. Seven others who were hospitalized have been released.