AMSTERDAM (Reuters) - Dutch police arrested 12 passengers on a U.S. Northwest Airlines plane bound for India which was forced to turn back to Amsterdam's Schiphol airport on Wednesday, news agency ANP reported. ANP quoted a police spokesman as saying 12 were arrested, but declined to give further details due to the ongoing investigation. Police officials were not immediately available to comment. The Dutch Defense Ministry said earlier the pilot decided to turn back after the crew said several of the 149 passengers on flight 42 to Mumbai were behaving suspiciously. Security has been increased at airports worldwide in the...