Dennis Hastert may be on the hook for $1.8 million of unpaid hush money to a man who has alleged the former speaker of the U.S. House of Representatives sexually abused him when he was 14.

The man filed a lawsuit in Kendall County, Illinois, where the alleged sexual abuse took place while Hastert was a high-school wrestling coach in the town of Yorkville, according to the New York Times.

The man is identified as James Doe in this suit and as Individual A in a separate court filing made by federal prosecutors this month. The man is one of four alleged victims of the lawmaker-turned-lobbyist in the federal case. The prosecutors’ filing represented the first time they had confirmed that Hastert had agreed to pay hush money and was not the victim of extortion by Individual A.

Criminal extortion could have led to charges against the alleged victim, but investigators concluded that Hastert and Individual A had mutually agreed to the payments, a move similar to an out-of-court settlement.

“It’s rather unorthodox and unusual, but if they had a verbal agreement I don’t see why it can’t be enforced,” Jeffrey Granich, an attorney who practices criminal and civil law in Chicago, told ABC News.

The period prescribed by the Illinois statute of limitations with respect to Hastert’s alleged sexual abuse expired long ago. But federal prosecutors have pursued charges against him for attempting to cover up payments of hush money by making numerous $9,000 withdrawals to avoid red flags at his bank, a crime known as structuring (and informally as smurfing) that can lead to a maximum sentence of five years. Attorneys for the government and Hastert have agreed on a maximum penalty of six months.

One of the four alleged victims in the federal case was identified by the media as Steve Reinboldt, who served as the high-school wrestling team manager in the late 1960s and early 1970s. He came out as gay to his sister in 1979 with a stunning claim.

“I asked him, ‘When was your first same-sex experience?’ He looked at me and said, ‘It was with Dennis Hastert,’” his sister, Jolene Burdge, told ABC News. “I was stunned ... And he just turned around and kind of looked at me and said, ‘Who is ever going to believe me?’”

Hastert served in the House as a Republican for 20 years after first being elected in 1986. He became speaker, replacing Newt Gingrich, at the beginning of 1999, serving until the Democrats captured the House in the 2006 elections. Later in 2007, he quit to become a lobbyist.