The affidavit shows that after the allegations were reported in July 2013, a detective interviewed someone in Spokane as part of the investigation. The person's name is redacted in the report.
The alleged victim told investigators Joshua Dolezal warned, "Don't tell anyone or I'll hurt you," according to the affidavit. It also says the person decided to come forward after the birth of Joshua Dolezal's daughter because of concerns about the child's well-being.
He was charged in March 2014 and is free on $15,000 bail, according to court records.
Joshua Dolezal is scheduled to face trial in August. Neither Dolezal nor his Denver-based lawyers responded to messages seeking comment. Fifth Judicial District Attorney Bruce Brown also declined to comment.
Ruthanne and Larry Dolezal, in an interview about their daughter with Spokane television station KHQ last week, avoided questions about any family legal matters in Colorado.
"It's better if we don't (comment)," Larry Dolezal told the station. "It's a separate matter."
On NBC's Today, Dolezal's parents said Monday they disclosed their daughter's true race because they didn't want to lie to an inquiring reporter.
"I think Rachel has tried to damage her biological family," Ruthanne Dolezal said. She said Rachel began to "disguise herself" after her parents adopted four African-American children more than a decade ago.