A Maine game warden found an 18-month-old missing toddler Monday, Sept. 19, in the town of Bradford.

According to a Maine Department of Inland Fisheries & Wildlife statement, the boy’s mother said she opened a door to let out the family dog very early Monday morning. She might have left the door open.

When the boy’s father woke up about 1 p.m Monday, he couldn’t find his son. The family searched around the Isthmus Road home before they called police, according to the statement.

Game wardens, state troopers with K9s, and a Maine Forest Service helicopter responded shortly after 2 p.m.

At 4:20 p.m. Game Warden Jim Fahey found the missing boy sleeping in a tire rut on a grassy road about 6/10 of a mile behind the residence. The boy appeared to be in good health, according to the statement.

The case remains under investigation by the Maine State Police.