McMillin resigned his position as a deputy prosecutor in Dayton, Ohio, on September 16, 2005, following allegations that he engaged in an improper sexual relationship with a crime victim and potential witness whose case he was investigating. The victim, Crystal Stapleton, alleged that McMillin made sexual overtures towards her in the summer of 2005 while investigating her then-boyfriend, John Gonzalez, for burglary, aggravated burglary with a firearm and domestic violence. In a complaint she filed against McMillin in 2006 for legal malpractice and breach of fiduciary duty, she claimed that she and McMillin subsequently engaged in a sexual relationship over the course of several weeks in early September. She also alleged that McMillin urged her, against her will, to testify against her boyfriend in court, even threatening her with arrest if she failed to comply. According to Stapleton's suit, Dayton prosecutors had a policy of dropping charges against suspects "in cases where the victim does not want to prosecute." First Assistant County Prosecutor Debra Armanini objected to Stapleton's accusation, claiming that no such policy existed. Gonzalez, Stapleton's boyfriend, subsequently pleaded guilty and was sentenced to 60 days in jail. McMillin claimed his conduct was not improper, as he removed himself from Stapleton's case on September 9, presumably because a sexual relationship with her was a possibility. He also noted that the Ohio Bar Association ruled that his behavior was ethical. Stapleton ultimately withdrew her complaint against McMillin in January 2007.