Dallas Area Rapid Transit issued the following announcement on July 7
On Wednesday, July 7, the Dallas Area Rapid Transit (DART) Police department held a memorial service honoring the sacrifice of the police officers from both the Dallas and DART police departments following a protest march in Dallas on July 7, 2016.
Dallas Police Sergeant Michael Smith, Senior Corporal Lorne Ahrens, Officer Michael Krol, Officer Patricio Zamarripa, and DART Police Officer Brent Thompson sacrificed their lives to protect the lives of others.
DART Police Officer Thompson, 43, became the first DART police officer killed in the line of duty when he gave his life, saving the lives of countless civilians and fellow officers.
Original source can be found here.