A grand jury said Wednesday they will not press charges against any of the Dallas police officers involved in using a bomb robot that killed the gunman who murdered five officers in a 2016 Black Lives Matter demonstration.

On the night of July 7, 2016, lone shooter Micah X. Johnson targeted unsuspecting Dallas police toward the end of a Black Lives Matter protest. Johnson, a former New Black Panther Party member, previously said he “wanted to kill white people especially white officers.”

Johnson gunned down and killed Dallas Police Department (DPD) Senior Corporal Lorne Ahrens, Sgt. Michael Krol, Officer Michael Smith, Officer Patrick Zamarripa, and Dallas Area Rapid Transit (DART) officer Brent Thompson. Nine others, including two civilians were injured.

Later, Johnson barricaded himself in a downtown community college parking garage in what became a lengthy standoff. Following hours of futile negotiations with the uncooperative assailant, then Dallas Police Chief David Brown made the unprecedented decision to take down Johnson with a remote-controlled bomb robot. Some experts called this the first time U.S. law enforcement used such a device to neutralize a suspect.

At the time, Brown said: “We saw no other option but to use our bomb robot and place a device on its extension for it to detonate where the suspect was.” He stated that other options “would have exposed our officers to great danger. The suspect is deceased as a result of detonating the bomb.”

Breitbart Texas reported that agents with the Bureau of Alcohol, Firearms, and Explosives subsequently searched the cop killer’s Dallas-area home. They found Johnson had enough explosives to “have devastating effects throughout our city and our North Texas area,” said Brown, who soon thereafter retired.

Authorities conducted an 18-month investigation into the Dallas police attack. They reviewed more than 100 hours of footage from police-worn body cams, the guns officers fired, and roughly 500 video files, including cell phone videos, private surveillance, and footage from the community college, according to WFAA. They also interviewed more than 240 people, most of whom were police officers.

This week, investigators brought their findings to a grand jury, according to a statement released by the Dallas County District Attorney’s Office:

As with all officer involved shootings, the Dallas County District Attorney’s Office presented the July 7, 2016, case involving the ambush of officers with the Dallas Police Department and the Dallas Area Rapid Transit Police Department to a grand jury. The Grand Jury returned a no bill.

The grand jury’s decision to “no bill” means the case is closed. The Dallas County District Attorney said they returned all evidentiary materials to the Dallas Police Department:

Our thoughts and prayers continue to be with the families of those who lost their lives that night, the officers who were injured, and all of the men and women who courageously put themselves into harm’s way, all in an effort to protect our community.

Dallas police also commented on the grand jury’s decision in a prepared statement:

The Dallas Police Department, DART Police Department, the families of the fallen officers, and our community will never forget the tragedy of July 7, 2016, and the impact it has had on all of us. We are pleased with the outcome of this investigation and we hope to continue to move forward with the healing process. Please continue to pray for the families of our fallen and the Dallas Police Department.

Since the tragedy, officers wear more protective gear at crowded events.

In 2017, Dallas police marked the one-year anniversary of their fallen officers in a bittersweet weekend-long memorial. They thanked the public for “Backing the Blue” through unprecedented outpourings of support in the immediate aftermath and the many months following the deadly attack.

Also last year, Texas Governor Greg Abbott signed into law the “Police Protection Act,” making it a hate crime to kill officers and judges. This legislation increased criminal penalties and punishments for an offense “committed against a person because of bias or prejudice on the basis of status as a peace officer or judge.”

Follow Merrill Hope, a member of the original Breitbart Texas team, on Twitter.