Hillsdale (Mich.) College, a four-year, private institution based on the "Judeo-Christian faith and Greco-Roman culture," is battling a sexual scandal that is sending shock waves through the broader movement of cultural conservatives.

Former Hillsdale president George Roche III, 63, is accused of engaging in a 19-year sexual affair with Lissa Roche, 41. Lissa Roche was married to Roche's son, George Roche IV, for 22 years, and was the mother of his grandson, George Roche V, a Hillsdale student.

Lissa Roche died of a gunshot wound to the head at the campus arboretum on October 17. Local police have since ruled her death a suicide.

George Roche IV told authorities that his wife confronted his father while the elder Roche was in the hospital. The elder Roche recently had divorced his wife of 44 years and had married again.

George Roche IV told National Review magazine that, after Lissa Roche spoke of an affair, he asked his father, "Is she telling the truth or is she having a breakdown?"

His father "didn't say a word," the younger Roche told the conservative publication. "I could tell by looking at him that she was telling the truth. I saw the look in his eyes. He was caught."

George Roche III has submitted a written statement to Hillsdale College trustees denying any sexual involvement with her. Roche resigned as Hillsdale president, with full retirement benefits, on November 10.

Conservatives have long praised Hillsdale—founded by free-will Baptists in 1844—because of its refusal, under Roche's leadership, to accept any federal assistance, even through grants or scholarships for any of its 1,200 students.

Roche became president of Hillsdale College in 1971, when the school was on the brink of financial ...