A Saint John mother is warning parents to keep an extra close eye on their children after her 14-year-old autistic son was taken from his backyard on Saturday afternoon.

Patricia Arseneau says Tyler was playing with his dog when two women persuaded him to get into their truck and go with them to the bank.

They brought him home safely, but swindled him out of the family's purebread pet, giving him $20 for the teacup chihuahua, she said.

"They told him that they were only taking him to get … dog biscuits."

Arseneau says she can't believe what the women did.

"What was going through your mind? Putting a minor in your vehicle and taking him uptown and giving him $20 for a purebred dog? I can't understand."

Arseneau contends the women must have realized her son's disability.

"Right away you would have known by the way he talks," she said. "Tyler is autistic. If you met Tyler, he has the mind frame of a five-year-old," she said. "He can't negotiate with people.

"They're trying to tell his worker that he tried to negotiate from a $100 to $20. And I'm like, 'No.'"

Arseneau says she called the police and when the two women heard the report on the scanner, they returned the dog.

She says police told her there's nothing they can do because Tyler volunteered to get into the truck and agreed to sell the dog.