Susan Powell, a 28-year-old mother of two young children, was reported missing Dec. 7 when she didn't show up for her stockbroker job at a bank. She was last seen a day earlier.
Her husband, Josh Powell, said he went camping with the couple's boys, ages 2 and 4, in subfreezing temperatures in the middle of the night Dec. 7 and returned in the evening.
West Valley City Police Capt. Tom McLachlan on Thursday said the 4-year-old boy was interviewed within "a day or two" after his mother was reported missing. The son told police his family went camping - an event his father has said coincided with her disappearance.
"I think the verification of the camping trip is important to the timeline on this," McLachlan said, cautioning against placing too much importance on the child's statement.
Meanwhile Thursday, Susan Powell's family members held a news conference in Washington state, where her parents live.
Eight members of Susan Powell's family were present, including her mother, two sisters, grandparents and a brother-in-law. As family friend and spokeswoman Shelby Gifford spoke about Powell's life, several members broke down in tears and embraced each other.
"Helpless, it just comes to mind. Totally dependent upon others. Impatient. I want my daughter to be back. I'm heartbroken she is gone," Cox said in an interview with The Associated Press in Puyallup.
The husband is not a suspect, but authorities said he has demonstrated a frustrating lack of cooperation that has only increased their suspicion of him. Police suspect foul play.
Investigators searched the Powell home for a second time in nine days Thursday, but would not disclose what was taken. Police have also searched Josh Powell's van.
Court records show that the family filed for bankruptcy in 2007, but Gifford declined to talk about the couple's financial history. She characterized their marriage as normal, with ups and downs.
McLachlan declined to comment on whether police had obtained a notebook or journal from Susan Powell's office, which reportedly detailed an alleged threat made by her husband about a year ago. Susan Powell's father, Charles Cox, said police found a wet spot in the home being dried by two fans, but police have declined to comment on that.
Investigators said there were no signs of forced entry at the home and they found Susan Powell's purse and cell phone there.
Gifford said friends and family members weren't surprised authorities named the husband a person of interest "given the events and his reactions to them in the past week."
"We know that Susan is an excellent mother and would not have tolerated her children being taken out of the home after midnight to go camping in dangerously cold conditions," Gifford said.
Meanwhile, police said investigators have discussed conducting a polygraph test of Josh Powell, but no such interview has occurred. "He is not allowing us the opportunity to interview him at length in order to verify his statements and also to get more specifics," McLachlan said. "His statements are absolutely vague."
Josh Powell's attorney, Scott Williams, disputed allegations made that his client had been uncooperative. Josh Powell has spoken to police and provided a DNA sample this week, as did several other family members. Williams, a defense attorney who often defends high-profile clients, described the DNA testing as routine in such cases.
Police have not sought to restrict Powell's movements by asking him to surrender a passport, because they don't have sufficient information to make that request, McLachlan said.
When asked what his reaction was to his son-in-law being named a person of interest, Cox replied: "I hope it's not true. I hope it's not true."
He added he believes his daughter is alive.
"As a father I can't give up the hope that she is still alive," Cox said.
Gifford said the couple's two boys - Charlie and Braden - are staying with Joshua Powell and at his sister's home at the moment. She said the family has access to the children, and Cox said he feels his grandchildren are safe with Josh Powell.
Josh Powell's brother-in-law, Kirk Graves, said the family is "not doing well," and struggling to deal with Susan's Powell's disappearance. He said Susan Powell's young boys - ages 4 and 2- have asked about their mother's whereabouts.
"It's coming up on Christmas and this is about the worst time of year to have the very worst thing happen to you," Graves said.
Jennifer Dobner reported from Salt Lake City.