An American Airlines was taken out of service after bullet holes were found in the wing.
However, it remains a mystery how and when it happened.
It came to light during a routine check after landing at Miami from Medellín, Colombia.
Colombia was informed and authorities there are investigating.
Local officials believe it may have been struck when landing at Medellin on Sunday.
“The aircraft was immediately removed from service for further inspection and repair. We will work closely with all relevant authorities to investigate this,” the airline said.
The airline said it did not cause any issues during the flight back from Colombia to Miami.
The Boeing 737 Max then traveled to Dallas for repairs.
