DALLAS (CBSDFW.COM) – The city of Dallas is preparing to remember the five police officers shot and killed during an ambush downtown on July 7, 2016.

Sunday night, downtown Dallas buildings will by lit up in blue.

Downtown Dallas lit up blue in honor of police officers (CBS 11)

Dallas Police Officers Lorne Ahrens, Michael Krol, Michael Smith and Patrick Zamarripa, and DART Officer Brent Thompson were killed in the line of duty in deadliest attack on law enforcement in the United States since September 11, 2001.

DART officer Brent Thompson and Dallas police officers Lorne Ahrens, Patrick Zamarripa, Michael Krol and Michael Smith.

The ambush happened as a peaceful protest against police brutality was coming to an end.

The gunman was later killed by a bomb robot after the attack and hours-long manhunt.

The Dallas Police Department is also planning a tribute to the fallen officers on Monday.