Hunks of wreckage from the crash of Malaysia Airlines Flight 17 arrived Tuesday in the Netherlands as the Dutch government rejected a call to hand over the investigation of the disaster to the United Nations. The flight was shot down July 17 over territory held by pro-Russia rebels in eastern Ukraine, killing all 298 people aboard, most of them Dutch. A law firm representing 20 relatives of victims from four countries has criticized the Dutch investigation as too slow and urged that it be turned over to the United Nations. With difficulty salvaging evidence from the crash site, investigators have yet to identify six victims.