Russia frees Ksenia Karelina, reportedly in exchange for Arthur Petrov
                                
                                
                                    (Newser) -
                                    A US-Russian dual national imprisoned in Russia  on treason charges  was freed Thursday in a prisoner exchange with Washington, the woman's lawyer and US Secretary of State Marco Rubio said, per the  AP . Ksenia Karelina, also identified in the media as Ksenia Khavana, is "on a plane back...