Kevin Johnson

USA TODAY

WASHINGTON — The number of felony suspects fatally shot by police last year — 461— was the most in two decades, according to a new FBI report.

The justifiable homicide count, contained in the FBI's annual Uniform Crime Report, has become increasingly scrutinized in recent months as questions continue to be raised about the use of lethal force by law enforcement.

National attention has been drawn to cases from New York to Albuquerque, though much of the focus is on Ferguson, Mo., where the restive St. Louis suburb awaits the decision of a grand jury weighing the fatal shooting in August of a black teenager by a white police officer.

The death of Michael Brown prompted weeks of protests and larger questions about the operations of a largely white department working in a majority African-American community. The Justice Department is conducting a parallel inquiry into the shooting Aug. 9 and a broader review into Ferguson law enforcement operations and whether the department has engaged in a pattern or practice of discriminatory policing.

This year, a USA TODAY analysis of the FBI's justifiable homicide database during a seven-year period ending in 2012 found an average of 96 incidents each year in which a white officer killed a black person.

The new 2013 total of justifiable killings represents the third consecutive increase in the annual toll. Criminal justice analysts said the inherent limitations of the database — the killings are self-reported by law enforcement, and not all police agencies participate in the annual counts — continue to frustrate efforts to identify the universe of lethal force incidents involving police.

University of Nebraska criminologist Samuel Walker said the incomplete nature of the data renders the recent spike in such deaths even more difficult to explain.

"It could be as simple as more departments are reporting,'' Walker said.

The Nebraska criminologist has been among the most vocal advocates calling for an all-inclusive national database to closely track deadly force incidents involving police.

"It is irresponsible that we don't have a complete set of numbers,'' Walker said. "Whether the numbers are up, down or stable, this (national database) needs to be done. ... This is a scandal.''

University of South Carolina criminologist Geoff Alpert, who has long studied police use of deadly force, said the latest number of justifiable homicides, while increasing, still likely represents a significant under-counting.

He said most major agencies have strongly supported close tracking of deadly force incidents. But he said the majority of police agencies in the country are small -- with fewer than 50 officers -- and their reporting practices involving such cases are not always uniform.

"Unfortunately, I think there has to be a government mandate for this kind of reporting that ties the responsibility to the communities' eligibility to receive federal funds.'' Alpert said. "It has to happen, because it has gotten to be an embarrassment.''

At least seven U.S. police departments have been the subjects of federal reviews in the wake of fatal police shootings since 2010.

In addition to Ferguson, one of the broadest examinations has been occurring in Albuquerque where the Justice Department last month announced an agreement that requires the city's troubled police agency to transform its lethal force policy.

Since 2009, according to municipal records, Albuquerque officers have been involved in nearly 50 shootings, with at least 32 resulting in death, including several mentally ill suspects.