Funeral Service for Final Slain Dallas Police Officer Patrick Zamarripa

Family, friends and law enforcement mourned the slain officer at a service.

Originally from Fort Worth, Zamarripa was a veteran who served three tours in Iraq before coming home and joining the Dallas police force. Family members said he loved his job, but most of all, he loved being a father to his stepson and 2-year-old daughter, Lyncoln Rae.

"He was so proud and loved being a father to her," his mother, Valerie Zamarripa, told ABC News' "20/20." "She looks just like him... I just don't know how she's going to be looking for him and not see him anymore."

Dallas Police Chief David Brown eulogized the fallen officer at the funeral service and appealed to the public for support as police-community relations are strained over the national conversation on race and policing.

"A house divided cannot stand. Our relationships with each other have to be reconciled," Brown said. "This family is grieving. We need to know that you support us. The family needs to know that you support us."

At least 12 officers were shot -– five fatally –- as dusk descended on a protest rally in Dallas. Two civilians were also injured. The suspected gunman was identified as Micah Xavier Johnson, 25, who was killed in an hours-long standoff with police. Officials said that it appears Johnson, who had no criminal history, acted alone.

Police spent hours negotiating with Johnson before detonating an explosive strapped to a robot and killing him. Police said Johnson told hostage negotiators that he was angry about recent fatal shootings of black men by police elsewhere in the United States and that he wanted to kill white people, especially police officers.