Clark County Sheriff Douglas Gillespie, who runs the Las Vegas Metropolitan Police Department, said the disclosures will help clear a backlog of cases awaiting public review and make the department more transparent.
The department, with more than 5,000 employees, has drawn criticism from civil rights groups who say that some officers engage in heavy-handed use of force with few repercussions.
"I think the sooner we get this information out, the better off everyone will be," Gillespie said.
He added that he hoped to improve the public's understanding of fatal confrontations.
"Whenever one of our officers use force, the public often doesn't often see all of the elements surrounding that split-second decision," Gillespie said.
The first three reports posted on the police department website Monday involved cases from November and December 2010. More than a dozen reviews are pending. Gillespie said he promised to release all of the reports, along with documentation on any discipline stemming from the review.
The idea, Gillespie said, is "to explain what steps have been taken by our agency to hold ourselves accountable."
Gillespie's announcement came with the Nevada Supreme Court preparing to hear arguments Tuesday on a constitutional challenge to a stalled Clark County coroner's inquest system, and state lawmakers due to take testimony a day later about public reviews of police slayings.
The department's critics point to a Las Vegas Review-Journal analysis in November that tallied 142 people killed in 378 police shootings in the Las Vegas area since 1990. The newspaper concluded that Las Vegas police use deadly force at a higher rate than counterparts in other urban U.S. police agencies.
Calls for reform escalated after the death of 43-year-old Stanley Gibson, a Gulf War veteran who was unarmed when he was shot and killed by police in December after refusing to get out of his car in a northwest Las Vegas apartment complex parking lot.
The ACLU of Nevada and the NAACP asked for a U.S. Justice Department investigation. The federal government responded by beginning a "best practices" review by the federal Community Oriented Policing Services program.
Dane Claussen, American Civil Liberties Union executive director in Las Vegas, attended Gillespie's announcement Monday and offered a qualified endorsement.
"We support anything that Metro does to be more transparent," Claussen said. "On the other hand, simply releasing documents doesn't address the culture of Metro. We all know that officers are almost never fired or prosecuted."
Gillespie noted that the process of coroner's investigations has been stalled since 2010. There are currently 19 cases awaiting review. Since then, police officers have challenged revisions that county lawmakers made to the system.
The release of departmental documents won't substitute for coroner's inquests if that system resumes, he added.
In the absence of inquests, Clark County District Attorney Steve Wolfson has begun reviewing cases and issuing prosecutorial opinions about whether officers were justified in their actions.
To date, the district attorney has reviewed seven cases. Officers, including Nevada Highway Patrol troopers and police from Henderson and Las Vegas, have been cleared in each case.
Gillespie said he aimed to follow the prosecutor's opinions with the police department reports.