Kirk Ferentz has known for weeks that several of his Iowa football players were under investigation for illegal gambling. He said Friday at the team’s media day he didn’t know until recently that some were accused of wagering on their own games.“It can’t be compromised, the integrity of the game, that’s first and foremost,” Ferentz said. “That’s got to be protected, and that’s where everything should start.”Former players Arland Bruce IV and Reggie Bracy and current player Jack Johnson were charged Thursday on suspicion of tampering with records to disguise that they were college athletes and under the legal betting age of 21 at the time they placed wagers. Kicker Aaron Blom was charged last week.Bruce, Bracy and Blom are suspected of betting on Iowa football games in which they played, according to court documents.“To me it’s a deal-breaker if that is, in fact, proven to be true,” Ferentz said.Johnson is alleged to have wagered on football games in which he didn’t appear, as well as other Iowa sporting events. A student staffer also was charged.Bruce has transferred to Oklahoma State, and Bracy has transferred to Troy.A combined 15 athletes and staff at Iowa and Iowa State have been charged in the ongoing investigation.Ferentz said his team receives an annual presentation on NCAA rules prohibiting gambling.“I think we have to ramp up our education,” he said.The players’ wagers were placed on FanDuel and DraftKings accounts that were registered under the names of other people, usually a close relative who was over 21.The tampering charge is an aggravated misdemeanor punishable by up to two years in prison and a fine. That’s in addition to potential punishment meted out by the NCAA.The NCAA recently updated its gambling guidelines to permanently ban athletes found to have bet on their games, influenced the outcome of those games, bet on other sports at their school or knowingly provided information to someone engaged in sports betting.If a player places a bet on another school competing in the same sport the athlete competes in, he or she could be suspended for half a season and would be required to complete an educational program on sports wagering rules before becoming eligible for reinstatement.Ferentz said he thinks the guidelines should be stricter, but didn’t elaborate.“It’s probably time to take another step,” he said. “I’m not sure it’s aggressive enough based on the world we live in. But everything has to start there.”The state agency in charge of the criminal investigation, the Department of Criminal Investigation, has declined comment because its work is ongoing.The state Attorney General’s Office did not respond to a message seeking comment on what triggered the investigation. Iowa and Iowa State are the only two schools where athletes have been charged. It was unknown if athletes at other schools in the state are under investigation."There are 49 states by my count that play football, have college universities that play football,” Ferentz said. “I think it’s interesting that we’re the only state I’m aware of (where there’s an investigation). It’s more interesting that it’s the two (major) colleges in our state. It’s interesting how that came about. I’m not excusing anybody that’s involved.”It was unclear how many additional Iowa players are under investigation. Defensive lineman Noah Shannon acknowledged to being under investigation when he withdrew his name from the list of Iowa’s attendees to the Big Ten football media days to avoid becoming a distraction.“He’s in a holding pattern like all of the other players,” Ferentz said, noting Shannon hasn’t practiced recently because of an injury. “To my knowledge, he hasn’t been accused of any crimes. We’ll let it ride out, see what the NCAA has to say about it.”Shannon said Friday he isn’t frustrated waiting for word from authorities and the NCAA.“They’re taking their time doing their investigation, and I can’t be mad at them for that,” he said. “I mean, I broke a rule. I owned up to it.”Iowa Hawkeyes 2023 football schedule* Kickoff time and TV information TBA unless notedSept. 2: Utah State at Iowa, 11 a.m. on FS1Sept. 9: Iowa at Iowa State, 2:30 p.m. on FoxSept. 16: Western Michigan at Iowa, 2:30 p.m. on BTNSept. 23: Iowa at Penn State, 6:30 p.m. on CBSSept. 30: Michigan State at IowaOct. 7: Purdue at IowaOct. 14: Iowa at WisconsinOct. 21: Minnesota at IowaNov. 4: Iowa at Northwestern (Wrigley Field)Nov. 11: Rutgers at IowaNov. 18: Illinois at IowaNov. 24: Iowa at Nebraska, 11 a.m. on CBS