Of the two, the best chances for justice are probably for Sandra Bland. If an ordinary police officer would be suspected to have caused her death, there may even be a trial (with secret police, it is usually a different story). Notice that media has not yet accused anyone for her death.
Regarding MH17, governments are involved and much of mainstream media already published their conclusion that rebels / Russia / Putin are the guilty. However, we know such media has reported lies before (remember the alleged weapons of mass destruction in Iraq and so on). This time we must be skeptical and not let anyone fool us. The USA and Ukraine must also be seriously investigated regarding MH17.