Nearly a week after the 34-year-old mother of two was reported missing, those are the only leads into her possible whereabouts.
"We have found no additional clues or evidence," Shasta County Sheriff Tom Bosenko told HLN.
Last Wednesday, Papini went for a jog as usual, Bosenko said. Neighbors told authorities she was last seen in the mid- to late-morning or early afternoon. She wore a pink jogging top.
Later that day, her husband Keith arrived home and it was unusually quiet, he told CNN affiliate KRCR-TV.
"On normal days, I would open the door and my family comes, runs and give me a hug," he told the station.
Papini was not home. Nor were the couple's two children -- ages 2 and 4. Her husband told the station that he called their day care center and learned the children hadn't been picked up.
Keith Papini used an app to track down his wife's smart phone, KRCR reported. It was down the street from their home, off Old Oregon Trail.
"That's when I knew she had been taken or abducted, in my opinion," he told the station. Keith Papini reported his wife missing.
Bosenko said authorities have no information or evidence so far "to lead us that way nor to dissuade us that she wasn't abducted."
"Best mom I've ever seen"
Sheila Koester, Sherri's older sister, told the station
that Papini texted her husband that morning to see if he was coming home for lunch. He wrote back that he wasn't.
Koester and Sherri's sister-in-law, Suzanne Papini, both described the missing woman as a "supermom" who would not disrupt the routine of her children, according to KRCR.
"She is an incredible human being," Suzanne Papini told the station. "Best mom I've ever seen."
Authorities have used scent dogs and helicopters to search the area, Bosenko said. They have also been contacting registered sex offenders.
Bosenko said investigators have received more than 100 tips.
"If she is listening, I want to say, 'We are trying. We are trying the best we can and I am sorry I'm not there,'" a weeping Keith Papini told KRCR.
"I'm coming honey. I am trying. I'm doing everything I can and I love you."
He hasn't told the children their mother is missing, the station reported.