A total of 11 officers were shot at a protest that took place Thursday against police brutality.
The names of all five deceased officers have not yet been released, but they served in the Dallas Police Department and the Dallas Area Rapid Transit agency. DART tweeted that it was grieving the death of Officer Brent Thompson, 43, who joined the agency in 2009.
"To say our police officers put their lives on the line everyday is not a hyperbole, it's a reality," said Mayor Mike Rawlings in a press conference early Friday morning.
Dallas Police Chief David Brown said that he was proud of the officers and saw "the courage and professionalism and their grit to stay on scene to search for the suspects while we're vulnerable."
In 2015, 41 law enforcement officers were killed in the line of duty, according to FBI statistics
. The number of police killed in the line of duty had been on the decline, having fallen from 51 in 2014.
Here's a look at the deadliest incidents on law enforcement officers:
November 29, 2009
Four police officers
from the Lakewood Police Department in Washington were killed at a coffee shop. The four slain officers were: Lt. Mark Renninger, Officer Ronald Owens, Officer Tina Griswold and Officer Greg Richards.
They were killed in an ambush-style shooting. The suspect in that attack, Maurice Clemmons, was shot and killed by police after a two-day manhunt. Police said he intentionally targeted the officers after a series of run-ins with authorities.
In 1989, Clemmons had been given a 95-year prison sentence in Arkansas for a host of charges, including robbery, burglary, theft and bringing a gun to school, but his sentence was commuted in 2000.
March 21, 2009
Four police officers from the Oakland Police Department
in California were killed in two incidents on the same day. The gunman, Lovelle Mixon, 26, allegedly shot two Oakland patrol officers and fled to a nearby apartment building. Mixon then allegedly shot and killed two SWAT officers who burst into the apartment before police fatally shot him. A fifth officer was injured.
The four slain officers were:
Sgt. Ervin Romans, Sgt. Daniel Sakai, Sgt. Mark Dunakin and John Hege.
September 11, 2001
The terror attack is the deadliest day in U.S. law enforcement history, killing 72 officers, according to the National Law Enforcement Officers Memorial Fund
, a group that tracks law enforcement deaths.
The officers came from several different agencies
, including the Port Authority, New Jersey Police Department,
New York City Police Department, New York State Department of Taxation and Finance, New York State Office of Court Administration, New York City Fire Department, the FBI and the U.S. Secret Service. A U.S. Fish and Wildlife Service officer died in the crash of Flight 93, which crashed in Shanksville, Pennsylvania.
April 19, 1995
Eight federal law enforcement officers were killed in the Oklahoma City bombing. The officers came from the U.S. Secret Service, U.S. Customs Service, U.S. Department of Housing and Urban Development and the Drug Enforcement Administration, according to the National Law Enforcement Officers Memorial Fund.
The eight slain officers were: Assistant Special Agent in Charge Alan Whicher, Special Agents Cynthia Brown, Donald Leonard, Mickey Maroney, Senior Special Agents Paul Ice, Claude Medearis, Special Agents Paul Broxterman and Special Agent Kenneth McCullough.
who was convicted in the bombing of the Alfred P. Murrah Federal Building, was executed in June 2001.
February 28, 1993
Four Special Agents of the U.S. Bureau of Alcohol, Tobacco and Firearms were killed trying to serve a search-and-arrest warrant for illegal weapons at the Branch Davidian compound near Waco, Texas. Instead, a gun battle ensued with four ATF agents killed.
The four slain agents were: Conway LeBleu, Todd McKeehan, Robert J. Williams and Steven Willis.
The incident led to a seven-week stalemate, leading to the deaths of 82 Davidians, who followed their leader leader, David Koresh.