The marriage took place during a family vacation to Yellowstone National Park during the summer of 2001.
Before long, James Wallace Fall began alternating nights in the beds of his 49-year-old wife and his new "bride" in Mound.
Fall, now 58, saw nothing wrong with the fact that the bride was his niece or that she was 10 when they "married," according to Mound police.
He told the girl that it was God's will that they marry. He told police this justified their union, legally and morally.
"He absolutely believes what he's saying," said Jami Wittke, a detective with the Mound Police Department, who interviewed Fall. "He said the Bible tells him that it's OK to have a relationship with your niece, to marry someone" that young.
Fall was arrested in January and charged with criminal sexual conduct by the Hennepin County attorney's office.
Part of the reason for Fall's confidence in his own righteousness, say people who know him, is that he sees himself as being chosen by God.
"I've talked to family members and more than one has said Jim Fall believes he's a prophet of God, of Christ," Wittke said. "They were afraid of him."
His wife, Rosemary Fall, was also arrested after the unidentified victim, who is now 19, told police that her aunt had known about the arrangement and done nothing.
"She was well aware of everything that was going on," Wittke said. "The investigation shows she was told about it while still at Yellowstone."
Wife, niece denied abuse
James Fall, who will be in court later this month, cited quotations from the Bible to support his position, police said. The passages, many from Corinthians, largely deal with sex and marriage.
"Everything is permissible for me," from First Corinthians 6:12, was one of Fall's favorite passages, police said.
"The wife's body does not belong to her alone but also to her husband," from First Corinthians 7:4, was another.
The arrangement, investigators believe, lasted for almost nine years until the young woman walked into the Mound Police Department in January and bore witness against her uncle.
The niece told investigators that Fall maintained the relationship through coercion, threatening to kick her and her two brothers out of the house if she didn't go along.
In recent years police were called to the home to talk with Fall's wife and the niece about alleged abuse, but both denied it, according to police reports.
"He really believes that this is OK," Mound Police Chief James Kurtz said. "I don't know how long he's believed that."
'A firm set of beliefs'
James Fall has been in the Hennepin County jail for weeks awaiting trial.
He is scheduled to be in Hennepin County District Court later this month as part of a custody hearing involving a 16-year-old nephew living at his home who was taken away by the county after the sexual abuse allegations surfaced.
David Risk, Fall's lawyer, said he will ask the court to conduct a mental health evaluation on Fall to see how competent his client might be.
Fall's punishment, Risk said, might ultimately hinge on his religious beliefs.
"From a religious perspective this is very unusual," said Risk, who does not expect to use polygamy or religious freedom as a defense. "We need to explore his mental health. Mr. Fall has a firm set of beliefs. That is something we will have to look at. Some of his beliefs are outside the norm and would cause someone to question his competency."
Wittke and other Mound police officers said Fall knew what he was doing and had ready arguments about what he did and how he lived.
Investigators have not been able to determine whether Fall, who calls himself a Christian, has any formal religious training. Wittke said she was told that Fall's father was a minister at a church in Minneapolis decades ago.
Wittke said no one who knows Fall has come forward to say he needs medication or hears voices or somehow is not in control of his actions.
"He was very calm ... very open to talking about it," Wittke said. "He did not hold anything back. I think that when this all got started he searched the Bible looking for scriptures to tell him that it was all OK."
Other facets of the case
Police also are investigating possible fraud, a murder allegation and just how the victim and her two siblings came to live in the Fall home after the death of their father.
Following Fall's arrest, family members contacted the Anoka County Sheriff's Department to have investigators look at whether James Fall might have killed his brother-in-law, Phillip Johnson, possibly by poisoning him 10 years ago.
"We reviewed it," said Lt. Paul Sommer. "We talked to the medical examiner's office and everything was done ... the coroner said [Johnson] died of a heart attack."
The question of how the children ended up in the home after Johnson's death has yet to be answered.
"We cannot confirm he has any legal status with the children," Kurtz said. "We can't find any legal documents that he has legal guardianship."
That has spurred allegations that the Falls were taking monthly Social Security checks from the children and using that money to live on.
Police said they also are checking computers in the home for child pornography. Wittke said that Fall showed the victim pornography that usually depicted younger girls and older men.
As far as police can tell, there appear to be no other victims in the case. But a final ruling on that probably won't be made until after the computers are analyzed and the investigation is completed.
"It's a strange case," Kurtz said. "I've never encountered one like this before."
Heron Marquez Estrada • 612-673-4280