L.A. — The FBI may charge two brothers who allegedly boarded an L.A. to Tokyo flight with the same boarding pass, reports ABC News. <br /> <br />The flight was forced to turn back four hours into its journey when airline staff discovered an "unauthorized person." <br /> <br />The mishap happened after a pair of Tokyo-bound brothers, booked on different flights, were somehow allowed onto the same ANA flight on December 26. <br /> <br />According to ABC News, the feds allege that one used a duplicate boarding pass to do so. Law enforcement told CNN that the brothers had similar names. <br /> <br />While this case is suspect, there have been genuine flight mix-ups in the past. <br /> <br />Aviation expert Buck Rodger told CNN that there are three checks for passengers. These are boarding gate checks, in-flight destination announcements and assigned seating. Rodgers said that a combination of faults from these can create a flight mix-up. <br /> <br />Federal investigators are looking into the case but have not charged anyone, reported the BBC.