SCOTTSDALE, Ariz. (NewsNation Now) — The search continues for 20-year-old Najib “Jubi” Monsif. Monsif, who has autism and the mental capacity of an 8-year-old child, and vanished from his Scottsdale home between the hours of 2 a.m and 3 a.m. Sept. 23. His father was the last person known to have seen him.

Josie Monsif, Najib’s sister, spoke with NewsNation’s Marni Hughes on Monday. She believes someone kidnapped her brother.

“The worst thing to say would be his body would have been found by now nearby,” Josie Monsif said. “He’s out there somewhere and he’s just not alone.”

Najib’s family believes he’s fallen into the wrong hands, either meeting someone while playing video games or when he wandered off.

Scottsdale police detective John Heinzelman joined NewsNation Prime on Tuesday to discuss the latest efforts to try to get Jubi home.

“At this point, we’re going back to the basics. We’re starting from the house and working outward,” he said.

Heinzelman said the police department believes he’s most likely not on his own since he is on the spectrum.

“He has to have some sort of help to get out of the neighborhood where he is or we would have found him by now.”

Najib left behind his cellphone and doesn’t drive. Heinzelman said one of the things investigators are looking into is his online presence, which he says is pretty large.

“He has a Twitter account and some other Gmail and some other things that we’re looking at,” he noted. “We’re trying to see, is there any communication that we can follow up on? Is there someone that he spoke with the evening before he went missing that could give us a little bit of clue into what he was thinking at the time?”

Heinzelman said a lot of the online information is pending due to the legal paperwork but they are working to expedite the process. He also mentioned that police have spoken to the family and friends of Monsif.

“But as of this point, we don’t have any solid leads to go with to see where he may be right now.”

Police dogs have picked up Jubi’s scent and tracked it to a nearby Albertson’s grocery store about a half-mile away from his home. From there, he seems to have vanished without a trace.

Heinzelman said the department has reached out to several outside agencies and is actively working on the Monsif case.

“We have reached out to the FBI and other agencies throughout the valley as well as nationwide for any sort of help.”

Heinzelman said the community has also been a big help in the search.

“We’re reaching out to whoever, whoever has information, whoever can help us find him, we’ll gladly take anything we can get.”

Najib is about 5 feet, 10 inches tall with a thin build and is possibly wearing all-black clothing. His sister also said he walks with a distinct shuffle.

Anyone with information is asked to contact the Scottsdale Police Department at 480-312-5000.