Hillary Clinton, commenting on the killing of five police officers by a black army reservist in Dallas and police killings of black men in Louisiana and Minnesota, said on Friday much more needed to be done to support police and innocent Americans who get into potentially deadly encounters with police."We must do more to have national guidelines about the use of force by police, especially deadly force," Clinton, the presumptive Democratic presidential nominee, told CNN. "We need to do more to look into implicit bias, and we need to do more to respect and protect our police. Look at what happened in Dallas. Those police officers were protecting a peaceful protest."