DALLAS — Steps away from pictures of the five officers killed last week by a lone gunman, President Barack Obama, former President George W. Bush and Dallas Mayor Mike Rawlings said Tuesday the best way to honor their lives is for Americans to open their hearts to one another and unite. “With an open heart, we can worry less about which side has been wronged and worry more about joining sides to do what is right,” Obama said at an interfaith service honoring Brent Thompson, Patrick Zamarripa, Michael Krol, Michael Smith and Lorne Ahrens. Obama, Bush and local leaders addressed a sea of black suits, dresses and uniforms at the Meyerson Symphony Center, where an estimated 2,500 people attended the service. Throughout the dimly lit room, attendees sported yellow and blue sashes representing the Dallas community and its first responders, respectively. The stage for the memorial was adorned with photos of the five fallen officers, as well as an array of flags representing North Texas cities that were among the first to rally for Dallas on Thursday. The five officers died when Micah Xavier Johnson, 25, opened fire on police Thursday night, striking 10 Dallas Police Department officers and one from the Dallas Area Rapid Transit Authority. The shooting came at the end of a peaceful protest by hundreds against the two recent police killings of black men Alton Sterling in Louisiana and Philando Castile in Minnesota.