Tuesday marks 10 years since five officers died in an ambush in downtown Dallas.

On July 7, 2016, a sniper opened fire at a Black Lives Matter protest, killing four Dallas police officers and a Dallas Area Rapid Transit officer.

Nine other officers and two civilians were also wounded in the attack.

The Dallas police department will hold a ceremony on Tuesday to pay tribute to officers Lorne Ahrens, Michael Krol, Michael J. Smith, and Patrick Zamarripa.

DART will honor the life, service, and sacrifice of DART police officer Brent Thompson. Officer Thompson remains the only DART police officer to make the ultimate sacrifice in the line of duty.

The shooting was the deadliest incident for U.S. law enforcement since the Sept. 11, 2001 attacks. The lone gunman, 25-year-old Micah Xavier Johnson, fired on the officers from an elevated position as they were working the peaceful protest in downtown Dallas.

Police said Johnson, who was an Army Reserve veteran, fled the scene. He was eventually cornered in a parking garage during a lengthy stand-off. After an exchange of gunfire, officers attached explosives to a bomb robot and detonated them near Johnson, killing him.

A permanent memorial honoring the fallen officers has been on display for several years outside of the Dallas police headquarters building on Botham Jean Boulevard. The 14-foot-tall sculpture was unveiled in 2019 and depicts busts of each fallen officer from the ambush.

The department has also parked a DPD squad car and a DART police unit next to the memorial outside the building.

On the anniversary, Downtown Dallas will also be lit blue to honor the fallen officers.