MINNEAPOLIS -- Despite concerns about authenticity, the bids keep rolling in for a piece of bubble gum supposedly chewed by Arizona Diamondbacks all-star Luis Gonzalez.

A 19-year-old Milwaukee man placed a $3,400.01 bid for the gum Thursday. The highest bid by Monday will get the used gum.

"As long as I know my money is going to charity that's all that matters to me," said Jamie Elder.

An Indiana University (Pa.) student told the Star Tribune of Minneapolis on Thursday that he was withdrawing his $3,275 bid after newspaper accounts documented the criminal history of auctioneer Jason Gabbert, of Wood Lake, Minn.

Gabbert, 32, said he coaxed a security guard to grab the gum after Gonzalez spit it out during a March 7 spring training game in Tucson, Ariz. He later started an online auction on his Web site to raise money for a local high school.

Lakeview School officials in Cottonwood, Minn., said this week they had no knowledge of Gabbert's plan until hearing it from the media.

In recent days, questions about the gum's authenticity also surfaced.

Earlier this week, the security guard who was said to have retrieved the gum for Gabbert disputed the account, saying that the gum was not Gonzalez's.

In an interview Thursday, Gabbert said most people don't have any qualms about the gum's authenticity and that he expects the bids to increase considerably by Monday's deadline.

In an effort to resolve the issue, Gonzalez agreed to chew another piece of gum in front of witnesses Thursday and forward the gum to an Arizona radio station.

According to the KRQ Radio Web site, Gonzalez will chew gum before the game against the Colorado Rockies Thursday night in front of a crowd. He will spit that gum into a water bottle. That gum will be sent to the The "Johnjay And Rich" radio program, the station's Web site said. The station will then auction off the gum for charity.

Gabbert, a sports memorabilia collector, has a history of criminal activity involving passing bad checks and fraud.

The former sportswriter attracted national attention in August 1993 when he was arrested in Fargo, N.D., for trying to open a bank account using the name of a Boston Red Sox pitcher. He pleaded guilty to attempted theft by deception and was sentenced to two years probation.

In 1997, he pleaded guilty to a fraudulent-schemes charge in Arizona that ultimately landed him in prison after he violated terms of his probation by leaving the state to return to Minnesota.

While in Minnesota, he pleaded guilty in Kandiyohi and Stearns counties to passing bad checks. He also pleaded guilty in Lyon County to a misdemeanor charge of "unlawful acts" after he bought a vehicle under an alias.