NEW : Five people detained in connection with deadly attack , police say . China censors video of car that crashed into Tiananmen Square , killing 5 . Chinese diaspora group says it 's too early to assign blame .
NEW : Five people detained in connection with deadly crash , police say . China censors images of jeep that plowed into Tiananmen Square , killing 5 . Uyghur diaspora group says it 's too early to assign blame .