By David Spunt

PHILADELPHIA (CBS) — The former head of the Bureau of Alcohol, Tobacco, Firearms and Explosives in Philadelphia says he is concerned about a piece of equipment that turns a semi-automatic weapon into an automatic weapon.

Sam Rabadi ran the ATF in Philadelphia and spent 25 years with the agency. He retired last week. He was restricted in his public comments when he was at the ATF, but now he’s candid and concerned.

“What I believe you have is an individual with some type of mental illness,” Rabadi said about Las Vegas shooter Stephen Paddock.

Gun Sellers: Customers Rushing To Buy Bump Stocks Since Las Vegas Mass Shooting

Authorities say Paddock used bump stocks on his weapons, as he killed 58 people and hospitalized hundreds. Those bump stocks are selling across the country like hotcakes in stores and in gun shows.

Authorities say the Paddock tried to purchase tracer rounds, which give off a pyrotechnic like effect to illuminate the direction of the round.

Rabadi says it would have caused even more deaths had Paddock been able to purchase them.

As the victims are laid to rest, the focus shifts from Las Vegas to Washington, D.C., where Rabadi feels cautiously optimistic about bipartisanship.

“I wholeheartedly believe in the second amendment,” he said. “There’s no more of an ardent supporter of it than I am but I can also tell you there are some common sense measures that not only we could, but should be taking.”

Authorities say Paddock looked at venues in Chicago and Boston but there’s no indication he had his eyes on Philadelphia.

Lawmakers could soon take up the bump stock issue in a formal setting.