The 28-year-old West Valley City woman had endured an increasingly adversarial relationship with her husband, Joshua Powell, which included "egregious acts of control," said Shelby Gifford, a family friend and the spokeswoman for Susan Powell's parents, Chuck and Judy Cox.
At a news conference held in her hometown Monday -- more than two months after her Dec. 7 disappearance -- the family said Susan Powell confided in a close friend that her husband was physically abusive at least once, but she did not seek medical assistance or file a police report. They would not provide any other details about the alleged incident.
Jennifer Powell Graves, sister of Joshua Powell, said that Susan Powell told her she had a physical altercation with her husband about 18 months ago. She declined to provide further details.
Police and court records show Joshua Powell has never been arrested for or charged with abuse against his wife. His attorney, Scott C. Williams, was not available to comment on the allegation Monday.
Susan Powell's family shared other insights into the couple's relationship that, they say, exemplified Joshua Powell's efforts to control his wife's life.
While family and friends knew Susan Powell enjoyed gardening, they said what they didn't know was that, for her, it was a survival tactic: Her husband refused to give her money she needed to feed her family.
"She was told she needed to grow the food that her children ate," said Gifford.
Joshua Powell isolated his wife by preventing her from using the family car and constantly changed the access codes to their bank account, despite the fact that she earned most of the family's money, Gifford said.
She said Joshua Powell also worked to alienate Susan Powell from her children. He often tried to "undo" his wife's parenting efforts, such as taking the children out of bed and telling them their "Mommy is so mean" after she put them down for the night, Gifford said.
"We didn't have all the pieces," Gifford said. "Everyone knew just a little bit. It is heartbreaking for us to know these things happened to someone we love so much."
Powell had suggested to family and friends she would end the relationship by their April 6 anniversary if the relationship didn't improve. Her family says they are not sure whether Joshua Powell knew about that deadline.
Powell's main concern in leaving her husband was the welfare of her two sons, now ages 3 and 5, Gifford said. Her husband threatened several times to take their children from her if she left, a threat she took seriously, Gifford said. She never mentioned she was afraid for her own safety.
Joshua Powell remains the only named person of interest in his wife's case, and police have searched his van and the West Valley City home the couple shared several times, said Judy Cox. Police have said Joshua Powell told them he took the couple's two sons camping at 12:30 a.m. the day Susan Powell disappeared.
Joshua Powell has moved back to Washington with his children and rented out the couple's Utah home. Charles and Judy Cox saw their grandchildren for about three hours on Christmas Eve, Christmas Day and Jan. 3, but said their son-in-law has refused visits since then.
"I have concerns for their safety -- emotionally at least," Charles Cox said.
The Coxes said they have not spoken with their grandchildren about their mother's disappearance.
Susan Powell's family has taken her story to national media outlets with the desperate hope that someone will be able to help.
Most recently, the family appeared on a special episode of "Dr. Phil," the second-highest-rated daytime talk show, which will air today.
"He didn't do a normal show," said Charles Cox, who said the entire show is dedicated to the issue of finding missing family members.
John Green and Ed Smart, both fathers of young women who were abducted, will also appear on the show, he said.
-- Sheena McFarland contributed to this report.
The Cox family on Monday announced the start of the Susan Cox Powell Foundation, aimed at helping families of missing persons.
"We have found that the opportunity to talk with family members who have endured this unique trial was of tremendous value to us when Susan went missing," family spokeswoman Shelby Gifford said. "We hope to provide the same strong shoulder and caring heart to families of missing persons that others have granted us during this difficult time."
A page of the foundation's Web site, susancoxfoundation.org, is dedicated to listing missing persons. For now, only one name is listed: Susan Powell, missing from West Valley City, Utah, at 12:30 a.m. on Dec. 7.
The site says the foundation will also support domestic violence prevention efforts.
But starting a foundation in Susan Powell's honor doesn't mean her parents are giving up hope.
"If Susan is gone, well, we've got to start," Charles Cox said. "If she's not, she'd love to be involved."