A Northwest Airlines flight from Amsterdam to Mumbai returned to the airport after takeoff when 12 passengers were seen acting oddly in a way that concerned other passengers. The passengers pulled out cell phones during the flight and would not remain seated when the fasten seatbelt light was on. This caused a major ruckus, and sky marshalls contained the passengers as the plane returned to Amsterdam. The passengers have not been arrested but can be held for 3 days without being charged (or I suppose they can be sent to Guantanamo for 3 years without being charged). This appears for now to be a giant case of nothing. The flight will attempt to leave again today.
FOLLOW UP: It turns out that it was, in fact, a giant case of nothing. All 12 passengers were released.