-- The alleged "misconduct" referenced in the indictment of former House Speaker Dennis Hastert is of a sexual nature involving a male individual, dating back to Hastert's time as a high school wrestling coach and history teacher in Yorkville, Illinois, sources with knowledge of the case told ABC News.
Associates and former colleagues of Hastert expressed surprise and dismay today over allegations that he disbursed $1.7 million in hush money payments to conceal alleged misconduct from a period before he entered politics.
The school district that employed Hastert from 1965 to 1981 as a high school history teacher and wrestling coach noted it "was first made aware of any concerns regarding Mr. Hastert when the federal indictment was released" Thursday.
The indictment revealed that Hastert's time at Yorkville, in Illinois, is "material" to the allegations against him and the U.S. Attorney's investigation. The indictment itself does not mention what the alleged misconduct is.
A statement released by Yorkville Community Unit School District #115 added it "has no knowledge of Mr. Hastert's alleged misconduct, nor has any individual contacted the District to report any such misconduct. If requested to do so, the District plans to cooperate fully with the U.S. Attorney's investigation into this matter."
A spokesman for Dickstein Shapiro LLC, the lobbying firm that Hastert joined in 2008 after leaving Congress, confirmed in a brief statement that "Dennis Hastert has resigned from the firm."
Ron Safer, a former U.S. prosecutor in Chicago who is now in private practice, said the indictment "is weird for a hundred different reasons."
"If you are trying to keep everything secret, you don't indict," Safer told ABC News. "Because eventually this information will have to come out either when he pleads, because that’s public, and a factual basis will have to be revealed," Safer told ABC News. "I cannot imagine a judge sealing that. ... The public has a right to this kind of information. This guy is a public official."
"Even though Speaker Hastert served as the Speaker of House in the other party, there's nobody here who derives any pleasure from reading about the former speaker's legal troubles at this point," Earnest said. "As a more general matter, the responsibility that the Department of Justice has to make sure that our public officials are not violating the public's trust is an important responsibility. And again I won't speak to any of the specific cases but the president certainly believes they have an important job to do and expects them to do it."
"I'm very disappointed in what I've heard and I want to find out more about it," Santorum told CNN today. "To see this kind of revelation is really upsetting. I feel bad for everybody involved."
Margaret Matlock said she taught physical education at the high school during Hastert's time there and recalls he had a highly regarded reputation.
"Everybody adored him because he was the wrestling coach and they were always winning state champions," Matlock said.
David Corwin, whose son Scott Corwin was on one of the wrestling teams coached by Hastert, said the former speaker was a devoted coach and teacher.
"He was a good coach. He took them to wrestling camps in the off season and he did whatever he could for them. He was a good teacher. Couldn't have asked for a nicer guy," David Corwin said.
Hastert has not responded to multiple requests for comment by ABC News.
ABC News' Jordyn Phelps and Devin Dwyer contributed to this report.