SCOTTSDALE, Ariz. (NewsNation Now) — Saturday, Oct. 23 marks one month since a 20-year-old Arizona man with autism disappeared from his home in Scottsdale, Arizona.

Najib “Jubi” Monsif has the mental capacity of an 8-year-old, according to his family. They describe him as innocent and vulnerable and fear he could be in danger.

His sister, Josie, is concerned the investigation may have hit a wall.

“Not so much that it’s slowing down in the way that the police aren’t doing their best, but they are doing everything they can and they’re hitting a wall where they’ve searched electronics, they’ve searched surveillance and there’s no evidence of a clue of where my brother could be,” she said.

Josie said her family is growing increasingly nervous as the one-month anniversary of his disappearance approaches.

“As a family, you just start to panic as to what to do next. As you know, time is of the essence right now. And even the initial belief that a search dog traced his scent to a nearby Albertsons was proven not to be accurate. They searched all the cameras, all the Albertsons and neighboring businesses, he was not there,” she said.

Josie believes that someone picked him up either right outside their home or in the neighborhood.

While Jubi has the mental capacity of someone much younger, Josie believes he would be able to ask for help if he was in need of it.

“I believe that if it was up to him, he would ask for help. And he would want to come home and he would ask anyone for help,” she said. “But who knows what kind of situation he’s in. This isn’t a normal situation for him to be let alone be without a family member. Who knows what kind of mental state he’s in, or who he’s with? But absolutely, he would ask for help.”

If you have any information on Najib “Jubi” Monsif’s whereabouts, you’re asked to call (480) 312-5000.