A 9-year-old boy managed to hop on a flight last week from Minneapolis to Las Vegas, alone and without a boarding pass, CNN reported. What exactly a child was doing on a flight to the notorious Sin City is a mystery.

CNN reports that officials are trying to figure out how the child, who was not identified, got through security and ended up boarding the plane. Patrick Hogan, a spokesman for the Minneapolis St. Paul International Airport, said the flight crew became suspicious of the child’s circumstances and contacted Child Protective Services in Nevada.

“The flight crew took appropriate actions to ensure the child’s safety, so the story does have a good ending,” Hogan said. Delta is a participant in the unaccompanied minor program where children between the ages of 5 and 14 can travel alone. But the parents must give permission for the child to travel and a representative of Delta accompanies the children from check-in to boarding.

“I don’t know of any other instance in my 13 years at the airport in which anything similar has happened,” Hogan said. The Transportation Security Administration is investigating.