Officers in Tamir Rice shooting to face a new administrative review

The two Cleveland police officers involved in the fatal shooting of 12-year-old Tamir Rice will face a new administrative review after a grand jury decided not to press charges against them, Mayor Frank Jackson said Tuesday.

SEE ALSO: Donald Trump Takes Aim at Bill Clinton for 'Sexism'

Regardless of what the grand jury in Cuyahoga County believed about the Tamir's death on Nov. 22, 2014, "it should not have happened," Jackson said at a news conference Tuesday.

"It should not have happened," he repeated. "It simply should not have happened."

County Prosecutor Timothy McGinty said Monday that it was "reasonable" for rookie cop Timothy Loehmann, who fired the fatal shots, to believe that they he was in danger when Tamir reached for what turned out to be a pellet gun.

"He had reason to fear for his life," McGinty said.

See photos from the case:

The two Cleveland police officers involved in the fatal shooting of 12-year-old Tamir Rice will face a new administrative review after a grand jury decided not to press charges them, Mayor Frank Jackson said Tuesday.

Regardless of what the grand jury in Cuyahoga County believed about the Tamir's death on Nov. 22, 2014, "it should not have happened," Jackson said at a news conference Tuesday.

"It should not have happened," he repeated. "It simply should not have happened."

County Prosecutor Timothy McGinty said Monday that it was "reasonable" for rookie cop Timothy Loehmann, who fired the fatal shots, to believe that they he was in danger when Tamir reached for what turned out to be a pellet gun.

"He had reason to fear for his life," McGinty said.

Loehmann and his partner, Frank Garmback, remain on restricted duty — "basically in an office doing paperwork" — pending the new review, Jackson said.

SEE ALSO:Sherrif: 'Affluenza' teen threw going-away party

"I do not have a comment on what the grand jury did," he said. "Now, it's in our world, and we are going to do what we believe is the right thing."

Police Chief Calvin Williams said the administrative committee, which includes civilians, will start from scratch, beginning with the initial calls to 911.

"We are going to take a lot at that from start to finish," Williams said Tuesday. "Once we look at all the evidence, the facts are going to be what they are, and we'll go from there."

Jackson and Williams said the city was ready for protests, saying they welcomed them as a part of the healing process.

"People are upset, and legitimately and rightfully so," the mayor said.

"You have an expression of legitimate concern about the system," he said. "That's what I'm hearing."

More from NBC News:
Bill Clinton to Stump for Hillary in New Hampshire
Trump, Pope Francis Tie for Second Place as Most Admired Man of 2015
Amid Latest Controversy, Trump Claims 'World's Greatest Memory'