Eight additional criminal complaints were filed Thursday in connection with an investigation into alleged student-athlete gambling at Iowa State University and the University of Iowa, court records show.

Four more football players with Iowa State are facing aggravated misdemeanor charges of tampering with records for allegedly falsifying "personal electronic sports wagering records by concealing [their] personal identity," according to the criminal complaints filed Thursday.

Four criminal complaints also were filed in connection with the University of Iowa's football program, where a current player, two former players and a graduate assistant all now face aggravated misdemeanor charges of tampering with records.

None of the individuals named in the criminal complaints filed in Story and Johnson counties have attorneys listed at this time.

"Since becoming aware of potential NCAA eligibility issues related to sports wagering by several of our student-athletes back in May, Iowa State University has been actively working to address these issues with the involved student-athletes, and that process remains ongoing," a statement provided to CNN by Iowa State Athletics said on Thursday. "We will continue to support our student-athletes as our compliance staff works with the NCAA to sort out questions surrounding their future eligibility for athletics competition."

The University of Iowa told CNN it "continues to fully cooperate with the investigation."

Authorities revealed last week that Hunter Dekkers, the starting quarterback for all 12 Iowa State football games last season, is among several athletes charged in Iowa district court in Story County in connection with an investigation into alleged student-athlete gambling at Iowa State University and the University of Iowa.

Dekkers faces a charge of tampering with records, with the state alleging Dekkers attempted to disguise his identity while betting on sports events. The criminal complaint alleges bets were made from Dekkers' phone using a DraftKings account set up under the name of a family member. He has denied the accusations.

A former Iowa State football player who was recently suspended by the NFL, a current Iowa State player and a wrestler also were charged.