Senator Clinton gave the following statement earlier this morning at approximately 10:30 a.m. CST.
"I just learned of the death of a Dallas police officer in a devastating accident that occurred as these motorcycle officers were leading our cars to this site. We are just heartsick over this loss of life and I have asked that my condolences be conveyed to the family. I will call them as soon as it is appropriate to do so. I have placed a call to the Chief of Police expressing my sympathy. This reminds us, once again, what our men and women in law enforcement do every single day and it is important that we respect and appreciate their service. I certainly am grateful for all they do for me and more importantly what they do for citizens in cities like Dallas and others across our country."
"I just want to express my deepest condolences to the family and to the Dallas police department on this tragic, tragic loss."
Hillary Clinton, Statement from Hillary Rodham Clinton Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/291175