An Alabama police officer went from cleared by his department to indicted for murder in the fatal shooting of Jeffrey Louis Parker, a mentally ill man.

Now the public is faced with competing narratives and little to no evidence about the case.

Huntsville Mayor Tommy Battle and Police Chief Mark McMurray say Officer William Darby did nothing wrong and isn't a murderer.

On the other hand, Madison County District Attorney Rob Broussard was "gravely concerned" about Darby's actions and took the case to a grand jury. At least 12 of the 18 grand jurors agreed with the DA and issued an indictment for murder.

"We have a different opinion than the district attorney has," said Mayor Tommy Battle after Thursday night's city council meeting. The council -- at the mayor's urging -- voted to pay thousands of dollars for Darby's defense using taxpayer money. Four of the five city council members say they haven't seen body camera footage of the shooting, and Council President Mark Russell didn't return a call for comment. The city has refused to release the videos to the public.

Huntsville Mayor Tommy Battle

Battle said since the indictment was issued he's had "some vigorous conversations" with Broussard about their competing conclusions in the case.

"We have no agenda that's trying to undercut any institution or any particular person," Broussard said in a Monday-morning interview with AL.com. Since that interview, Madison County Circuit Judge Donna Pate has issued a gag order.

"We review evidence and we get that evidence to the grand jury," Broussard said. "We do it in an above-board manner. That's my job and that's what we do."

The mayor, police chief, prosecutor and grand jurors all saw the body camera video. So why were their conclusions so different?

How was Darby cleared by a review board -- which includes the DA's office -- then indicted for murder, one of the most serious criminal charges in Alabama's law books?

The review board

While the district attorney's office is considered part of the police review board, the prosecutors do not vote or make decisions about whether officers should face disciplinary action.

Madison County District Attorney Rob Broussard

"Our area of inquiry is, 'Is there potential criminal liability or not?'" Broussard said.

"As far as policies and procedures of Huntsville Police Department, that's their business and we do not weigh in on that," the district attorney added. "We're not involved in any discussion or determination of whether or not somebody was at fault in policy."

In addition to the DA's office, the review board includes representatives from the city attorney's office and the police department's citizen advisory council. Those citizens -- who are chosen by the mayor, city council and police chief -- can give an advisory opinion about whether an officer acted in accordance with policy and training. But, neither those citizens nor the district attorney's office have a voting role in the review board process, said Huntsville police spokesman Lt. Michael Johnson.

"It's just the command staff that has the final say," Johnson said. Because of the judge's gag order, members of the police department aren't allowed to discuss Darby's case. Johnson said he could only comment generally about the review board process.

Darby and two other officers were put on desk duty at the time of the shooting. But about a month later, the review board cleared them to return to work. Since the indictment was announced, Darby has been put on paid leave.

Battle said he's unsure whether Broussard has heard the city's argument that Darby acted within the police department's policy and guidelines.

"Working within the guidelines is something that's important," Battle said. "And that's the point to say that we're going to support those people who work for us and work within our guidelines. We're not going to put them in harm's way."

Broussard is aware the police department cleared Darby but said that has nothing to do with whether the officer violated Alabama law.

The grand jury

Broussard said he was "gravely concerned" dating back to the review board meeting.

"The action we felt it required was put it to a grand jury," he said. Broussard's office doesn't send every police-involved shooting case to a grand jury, as some other prosecutors do.

"If in our opinion it's clearly justified, we don't present it to the grand jury," Broussard said. "And more often than not, we don't. But there are occasions where we do let 18 citizens have a look at it."

What's a justified shooting? If a person reasonably believes somebody is using or is about to use deadly physical force against them, that person is justified in using deadly physical force.

"It's just a common-sense review of the evidence -- do you believe it was justified or not? Broussard said.

As is typical, the grand jury heard hundreds of cases -- not just Darby's, records show.

Grand jurors are randomly selected. Unlike a jury that's convened for trial, the grand jury isn't subjected to the jury-selection process. Prosecutors tell grand jurors they can recuse themselves if they have a conflict of interest with any particular case, Broussard said.

At least 15 grand jurors are needed to convene and vote, though typically there are 18. It takes 12 votes to indict.

An indictment is far from a conviction. To issue an indictment, grand jurors have to decide there's probable cause to believe someone is guilty. For a conviction, prosecutors have to prove guilt beyond a reasonable doubt.

Neither the defendant nor his lawyer is generally present at the grand jury presentation, and the defense can't cross-examine witnesses.

The grand jury process is generally considered secretive. In Darby's case, the police department was aware the grand jury was convened.

"They were very much aware this was going to be presented," Broussard said. "There were personnel from HPD that testified."

The day of the shooting, officers briefly talked with Parker at the scene on Deramus Avenue. Parker, 49, called police, saying he was suicidal and had a gun. Darby commanded Parker to drop the gun, the department said. When Parker didn't follow orders, Darby shot him, the police said.

Darby, a 25-year-old from neighboring Morgan County, has been on the police force for two years.

Little is publicly known about Darby. The Huntsville city attorney's office has refused to release his personnel file, a set of documents that are generally considered public records.

Darby earned a degree from Pensacola Christian College and worked there as a security officer for about three years, according to his LinkedIn profile, which appears to have been taken down during the past several days.

Asked whether he expected the grand jury to indict Darby, Broussard said, "I was not surprised."

AL.com reporter Paul Gattis contributed to this story.