Who bought the Bradley Center's guitar autographed by members of the Eagles? It's a secret.

The recent auction of BMO Harris Bradley Center memorabilia didn't include one prominent part of the arena's collection: an electric guitar signed by members of the Eagles.

The Gibson Les Paul guitar was displayed in the Bradley Center lobby along with guitars signed by Prince, Garth Brooks and Neil Diamond. Those other instruments and a slew of other artifacts were sold earlier this month through an online auction that fetched about $160,000.

The Eagles guitar, signed by band members in 1995, was not included because it was sold in a side deal, said Bradley Center spokeswoman Brenna Sadler.

Who wound up with that guitar and several others and how much they sold for remains a secret.

"The vast majority of the Center’s memorabilia (95 percent or more) was included in the online auction," Sadler said in an email.

"Six pieces of memorabilia, including a couple of guitars and several framed photographs, were sold separate from the auction to a buyer as part of a large bundle that included furniture, equipment and the like," she said.

The items "all were appraised and sold at the appraised fair market value," she said.

"As with the public auction, the Center is not authorized to release the names of the buyers."

The Bradley Center said that bidders should assume that the instruments and microphones in the auction were not owned by or played by the musicians.

RELATED:Fender guitar signed by Prince sells for $25,000 in auction of Bradley Center artifacts

Sadler said there was no requirement for the Bradley Center to hold a public auction.

"Management and the board decided the online memorabilia auction would be a good way to generate funds to help cover the center’s closing costs and continue to share 30 years of memories with fans," she said. 

Decisions as to what items would be placed up for auction were made by the center, in conjunction with Great Lakes Auctions and considering requests made by historical societies for Bradley Center items.

The state Historical Society, for instance, asked for a guitar signed by rocker Bob Seger, she said.

The guitar signed by Prince, who died in 2016, sold in the online auction for $25,000. Other sales include guitars signed by Bon Jovi ($4,250) and Neil Diamond ($9,650).

The Eagles guitar was noteworthy because it included the autograph of one of the band's founders, Glenn Frey, who died in 2016.

The Bradley Center is closing in conjunction with the opening of the Milwaukee Bucks new $524 million arena just to the north. Built with $250 million in public money, the new arena opens in late summer.

The last public events were held at the Bradley Center in April. Demolition of the building will begin this fall.