Updated

Police say they suspect foul play may be involved in the disappearance of a 28-year-old mother of two from Utah.

West Valley City Asst. Police Chief Craig Black said Wednesday Susan Powell's disappearance is so out of character for her that police are treating the case like a criminal investigation.

Joshua Powell, whose wife disappeared from their West Valley City, Utah, home more than a week ago, is considered a person of interest in the disappearance of his wife, Susan Powell, said Assistant Police Chief Craig Black.

"We've been interested in what Josh has had to say all along," said Black.

Black said that detectives have met twice with Josh Powell. "He submitted to a search warrant and provided a DNA sample."

"I wouldn't characterize him (Joshua) as being cooperative."

Susan Powell was reported missing Dec. 7 when she didn't show up to work and her children weren't dropped off at day care.

Josh Powell told police he took his two boys, ages 2 and 4, camping around 12:30 a.m. that day and returned in the evening.

Investigators said they haven't been able to verify the camping trip because snow had covered the site — Simpson Springs on the historic Pony Express Trail in Utah's west desert.

The Powell home was locked when police arrived and they broke in, fearing the family had suffered from carbon monoxide poisoning. They found no signs of forced entry.

Susan Powell's father, Charles Cox, has said police found a wet spot in the house being dried by two fans when they entered.

West Valley City Police Capt. Tom McLachlan declined to comment on that, but said earlier Tuesday that Josh Powell was costing the police valuable time because he failed to show up for an interview on Monday.

"We are very disappointed in that because he is not a suspect and this delays the investigation — it slows things down," McLachlan said early Tuesday. "His stated purpose is he wants to find Susan and that is also our stated purpose on this missing persons case, and this complicates the issue."

McLachlan said police initially interviewed Josh Powell when he returned home and then again the next day. Police have also interviewed the Powells' older son.

Williams said the Monday interview was canceled at his request.

"We have been in contact with West Valley City police multiple times daily," he said. "The Monday afternoon possible interview was canceled by me that morning because I was new and because I needed more information to provide effective consultation and advice."

Williams is a Salt Lake City defense attorney who often represents high-profile defendants in criminal cases. He declined to specify exactly when he was retained by Josh Powell.

McLachlan said late Tuesday that he wasn't aware if police had met with Josh Powell on Tuesday.

"I'm going to have to wait to the morning to get briefed until I can make any statement," he said.

Kiirsi Hellewell, Susan Powell's best friend, said she has been in contact with Josh Powell on a daily basis but hasn't asked him specific questions about Susan in an effort not to interfere with the investigation or to lose his trust as a friend.

"He doesn't do a lot of talking. He mostly looks upset and confused and is crying most of the time," Hellewell said.

She said she sat next to Josh Powell at church on Sunday and that he cried through most of the service.

It was at that same church on Dec. 5 that the last known pictures of Susan Powell were taken. The couple and their children attended a Christmas breakfast, where one picture shows a smiling Josh Powell with a camera hanging around his neck, talking with his children while his wife stands a few feet away reaching for food.

"Susan and her family were very normal and seemed all happy to be there. We actually talked to them quite a bit. Josh seemed really happy to be there and he asked me to take a picture of he and the family, and yes he has the picture," Mindy Kay Perry Guzman, who took the picture, wrote in a message to The Associated Press.

Click here for more from Fox13Now.com.

The Associated Press contributed to this report.