A father and his young son who mysteriously disappeared after going for a walk have been found safe following a massive multi-state search.

Todd Sabatini, 36, and his toddler Theo left their home in McHenry, Illinois at around 12pm on Saturday.

Family described the outing as a 'normal activity' but became concerned when they failed to return by 4pm.

They contacted the McHenry Police Department, which began a frantic search and managed to locate Theo's abandoned stroller, before determining Sabatini had driven 65 miles to Wisconsin before vanishing again.

Just after 7pm on Sunday, police confirmed that the father and son had been found.

'We want to reiterate that both Todd & Theo have been found safely by our Detectives,' the department wrote on Facebook. 

'We want to extend a BIG thank you to our community, local agencies, and Wisconsin agencies for assisting in the safe return of Todd & Theo.'

Authorities have not released any further details about the case, including where exactly they were located. 

Family previously said the prolonged trip was 'unusual behavior' for Sabatini, who did not 'have the necessary provisions for an extended excursion with Theo,' PEOPLE reports.

Officers eventually discovered the 22-month-old's stroller abandoned behind a local business. 

They later also obtained security footage showing Todd with his young son at a Jewel-Osco supermarket 'attempting to make contact with someone within Zion Lutheran Church.' 

He also apparently spoke with someone at a local Taco Bell. 

It is unclear what the father may have been discussing with the locals.

Sabatini then obtained a rideshare and visited the Greenfield Police Department in Wisconsin, where he spoke with an officer. 

He then left the police station with his son in tow on foot at around 2pm.

'As this behavior is unusual, the McHenry Police Department is actively working with the Greenfield Police Department to check the welfare of Todd and Theo,' officers said.

By Sunday evening, McHenry police said they had 'reliable information putting Todd and Theo in Milwaukee in the last couple of hours.'

'We are actively conducting searches and follow-up investigation efforts in that area,' the police department posted on Facebook, noting that both the father and son are now listed as missing persons.

Sabatini was last seen wearing a blue and black flannel shirt with a gray tank top, jeans and Converse sneakers, while Theo was last seen wearing a blue shirt and dark-colored shorts.

Investigators noted that Sabatini previously had facial hair but is now clean shaven.

The father was active on Facebook just three days before he mysteriously vanished, sharing an image of him cradling Theo captioned with a heart emoji.