Susan Powell's father, Charles Cox, indicated to "Good Morning America" Monday that his faith in his son-in-law was wavering.
"I asked him if he had any idea where his wife, my daughter Susan, would be. And he said he didn't. He was sincere sounding when he said that. I believed that," Cox told "GMA."
When asked if he still believed his son-in-law, Cox replied, "I don't know what to think anymore."
Cox said that now he has no choice but to leave the investigation up to police.
"I understand the concerns I'm hearing from everyone, and I can see their point," he said. "I just don't want us to focus on him exclusively or that story exclusively when there might be another explanation."
Others also are confused by Powell's actions, including his decision to hire a lawyer.
Powell did not show up for a scheduled second interview Monday, police said.
"It kind of raises a red flag, but I know he has to protect himself," neighbor Wendy Trujillo told "Good Morning America." "We're just really worried about Susan. And of course, everyone's thinking the worst and just hoping by the faith of God that she does come back."
Trujillo told ABC News that police and forensic units have removed several bags and boxes as well as one of the family's computers. Joshua Powell and the couple's sons, she said, have not been staying at the house.
"She's been gone for an entire week. I don't believe there can be any, very much hope left," a tearful Kiirsi Hellewell, Susan Powell's best friend, told ABC News this week. "I'm trying to stay busy and not think about it. But I don't see how there's any way she can still be alive."
Joshua Powell told police his wife didn't go camping with them because she was feeling sick.
Cox said it's not unusual for his son-in-law to get a late start.
"It was believable," Cox said of Powell's story. "It was unusual, but believable to me."
But Hellewell said she talked to Susan Powell the day she went missing and she wasn't sick. Police told ABC News they couldn't verify Joshua Powell's camping trip because snow had covered the spot where he said they went.
The West Valley City Police found Susan Powell's purse and keys in her bedroom and say there was no sign of forced entry at the house.
"She would never leave her children, and she would never leave without contacting anybody," Hellewell said.
Susan Powell's friends told ABC News that although the couple openly had discussed marital and financial problems in the past and at one point were considering divorce, they had made a real effort to reconnect.
They both had good jobs, Hellewell told ABC News, and Joshua Powell had begun going back to church.
Anyone with information regarding the case can call West Valley City Police at (801) 840-4000. Crimestoppers has offered a $1,000 reward for information leading to an arrest in the case, Gifford said.