NORTHAMPTON — Police are using helicopters, a dive team and rescue dogs in an effort to find 36-year-old Jonathon Maxwell, who went missing this weekend and was last located in the Meadows area.

Less than two days since Maxwell’s sister contacted Northampton Police at about 9 p.m. Friday, informing officers that she had used the “Find my Phone” feature to locate her brother in Northampton, police have found Maxwell’s cellphone and car, Capt. Corey Robinson said in an interview Monday morning.

“At about 9 p.m., we responded to the area of Rainbow Road for a well-being check of a male party. His sister had indicated that his his cellphone was pinging that area. The sister lives in Connecticut. He’s got no ties in the area [and] no reason to be up here,” Robinson said. “Our guys went out there looking for him — looked for several hours, couldn’t find him. They did find his vehicle … It appeared it was stuck in the mud, so the vehicle was towed out of there.”

Robinson, explaining that Maxwell is not believed to be armed or dangerous, said police are concerned about his well-being after talking to his sister. He said that officers found Maxwell’s car after someone passing through the area reported a Blue Subaru matching his vehicle stuck in the mud on 1st Square Road. Officers later found his cellphone in a nearby cornfield.

Easthampton Police’s K-9 Unit assisted with the search Saturday night, while Northampton Fire searched the river alongside the Massachusetts State Police Air Wing and the State Environmental Police on Sunday.

Robinson said police are asking the public to stay clear of the area as the search continued Monday with the assistance of the State Police Dive Team, noting that police dogs are still scouring the area. He added that the search area’s size makes finding Maxwell a challenge for law enforcement and other emergency personnel.

“The whereabouts of Mr. Maxwell are unknown at this time,” he said. “It’s just such a vast area and we don’t know where he is. He could have wandered off into another town for all we know, but we’re going to give our best effort to try to find him.”

Northampton Police, in a Sunday Facebook post, asked anyone who lives in, works near or frequents the area of the Meadows to review any camera footage they may have and contact police at 413-587-1100 if they have any information about Maxwell’s whereabouts.