Two major retailers appear to have stopped selling bump stocks in the wake of the Las Vegas shooting.

Cabela’s and Walmart both removed bump stocks from their online catalogs as of Wednesday. Links found through a Google search of the bump stocks at Walmart triggers an error message when clicked, while Cabela’s lists the product as “sold out.” It’s unclear whether the products remain stocked at retail locations.

Slide Fire Solutions, a Texas-based manufacturer of bump stocks who provides the product to Walmart, Cabela’s and other retailers, posted a message on its website indicating new orders have been “temporarily suspended.”

Federal authorities confirmed Tuesday 12 of the 23 guns recovered from 64-year-old Stephen Paddock’s hotel room at the Mandalay Bay Resort and Casino were modified with bump stocks — legal devices that mimic automatic fire. The Bureau of Alcohol, Tobacco, Firearms and Explosives traced 47 guns Paddock owned back to retailers in Nevada, Utah and Texas.

Four days after the deadliest mass shooting in American history, however, authorities appear no closer to understanding why Paddock — a retired accountant and prolific gambler — opened fire from the windows of his hotel suite into a crowded country music festival 32 stories below, killing 59 and wounding nearly 500 others. He turned the gun on himself before a SWAT team could enter the room, leaving behind few clues as to his motivations.

“What we know is Stephen Paddock is a man who spent decades acquiring weapons and ammo and living a secret life, much of which will never be fully understood,” Clark County Sheriff Joe Lombardo said Wednesday. “He meticulously planned on the worst domestic attack in United States history.”

Law enforcement said Paddock had no criminal background or ties to any international terrorist organizations. His family said he wasn’t particularly religious, partisan or interested in guns, either.

FBI Special Agent in Charge Aaron Rouse told reporters Wednesday the investigation, so far, hasn’t given agents any sense of what inspired Paddock to perpetrate Sunday’s attack. He and Lombardo urged patience from the public, ignoring requests for conjecture regarding popular theories circulating on social media about the shooter’s motivations.

“Our resolve is strong,” Rouse said. “We will get to the bottom of this, no matter how long it takes.”