DALLAS (CBSDFW.COM) – Four years ago five police officers were killed in an ambush during the end of a Black Lives Matter rally though downtown Dallas. Outside Dallas police headquarters today, people stopped by the fallen officers memorial to pay their respects.

“I’m just reflecting ​back on four years ago, ​how heart-wrenching that ​evening was,” retired DPD Sgt. Mike Gurley said. ​”The average person, ​they were devastated by ​this, but as an officer, it’s probably the ​greatest impact of my 37 year career.” ​

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​Gurley knew the victims and had trained Michael Smith to work bike patrol during his time at North Central.

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“He was quiet as can be, a real unassuming guy,” he said. “​He’s just good all ​around. All those ​guys are good all around guys, just doing their job, protecting​ a protest of all things,” Gurley said as he shook his head.

“I’ll miss having ​lunch with the guys, hanging out with them and seeing them,” officer Ruben Lozano said.

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He stopped by the memorial today and dropped off flowers.

“Krol, Ahrens and Zamarippa were ​part of the Foxtrot unit and I was in that ​unit. There were nine of us… and it just ​so happened that I was off that day,”​ he said. “I knew my guys were going to be out there, but I didn’t think it would turn the way it did. Their legacy is ​going to live on through the people they touched.” ​

From the blue ribbons​ around trees outside DPD headquarters to ​the flowers and cards at ​the memorial, those closest to ​the five fallen officers said it’s evident that they were well loved.

“I feel them ​with me when I think about them all ​the time,”​ Lozano said.  “They’re with us in these ​trying times as law enforcement ​officers and they keep fighting  because you know love conquers all.”