Tickets for Metallica and several other groups were sold directly to the resale market with the co-operation of Live Nation, a new report in Billboard reveals. Fans have long suspected the practice to be prevalent in the music industry—it accounts for the rapid selling-out of high-profile concerts, tickets for which immediately appear at hiked-up prices on secondary sites.

These practices are controversial as they prohibit fans from purchasing tickets at face value through normal channels when they first go on sale. The parties responsible for moving mass quantities of tickets to the resale market are allegedly aware of this controversy. In a 2017 phone call reviewed by Billboard, Live Nation president of U.S. concerts Bob Roux said to an anonymous event promoter: “When this happens, 4,600 tickets into a single account, there may be some eyebrows that get raised.”

Live Nation representatives told Billboard that the company has been facilitating the transfer of concert tickets to resale outlets in this manner throughout the years, however they maintain that they have done so only at the request of the touring artist. Artists are technically in control of where their tickets are first sold, however many performers allow other members of their team to make those decisions. A representative for Metallica told Billboard that the members themselves were unaware of the practice, as the band had delegated the matter to a man named Tony DiCioccio, who was working with the group as a “ticketing consultant.”

Billboard reports that according to Live Nation, DiCioccio was inspired to move Metallica tickets to resale platforms after the band opened Minneapolis’ U.S. Bank Stadium in 2016 and turned a decent profit when more than 10,000 tickets were sold “on the secondary market without the band’s participation.” “After seeing the volume of secondary transactions for that show and the benefit being captured by brokers,” Live Nation told Billboard, “the independent consultant [DiCioccio] worked with Live Nation on a unique distribution strategy that used the secondary market as a sales distribution channel for select high-end tickets.”

In the phone audio obtained by Billboard, Bob Roux spoke to Outback Presents CEO and chairman Vaughn Millette about the resale strategy for Metallica tickets days before they were meant to go on sale. “That’s the part I’m trying to figure out with Tony [DiCioccio],” Roux reportedly told Millette. “You want to keep this quiet, but there isn’t a good way for the light bulbs not to go off.”

Read Billboard’s full report here.