United Airlines flight returns to Hawaii after concerning message found on bathroom mirror; FBI investigating

United Airlines flight returns to Hawaii after concerning message found on bathroom mirror; FBI investigating

Law enforcement met the plane and conducted a security sweep

A United Airlines plane bound for LAX turned around mid-flight Wednesday after a "potential security concern." (Joan Valls/Urbanandsport/NurPhoto via Getty Images)

Honolulu police referred questions about the investigation to the FBI. (Mitchell Layton)

The United Airlines flight being investigated by the FBI took off from Honolulu. (iStock)