Twelve police officers have been charged with a crime this year stemming from fatal encounters with people while on duty.
That's a record that stretches back at least 10 years, according to research compiled by Bowling Green State University criminal justice professor, Philip Stinson — an ex-cop whose data was cited by the Wall Street Journal.
There was an average of about five prosecutions of law enforcement officers each year over the last decade.
"Most jurors have the idea the cops are out to do the best job they can."
Tom Orloff, Retired San Francisco Bay area district attorney
There's little doubt about what may have contributed to this year's increase. Police killings have lately been the subject of intense media and political scrutiny.
And with civil rights groups pointing to one specific trend in these deaths — that they often involve unarmed people of color — it's not hard to understand why an increase in police prosecutions has occurred.
See photos from Black Lives Matter protests:
2016 groups shaping the election: #BlackLivesMatter
More police officers have been charged over civilian killings in 2015 than at any time in the last decade
FERGUSON, MO - SEPTEMBER 11: A makeshift memorial for Michael Brown Jr. is seen on September 11, 2015 in Ferguson, Missouri. 2016 Presidential Candidate Ben Carson is expected visit to the Ferguson area. Dr. Carson recently became under scrutiny after publishing an article criticizing the 'Black Lives Matter' movement in their quest against injustice and police brutality. (Photo by Michael B. Thomas/Getty Images)
NEW YORK, NY - AUGUST 09: People hold banners reading 'Black Lives Matter' during a rally to mark the one year anniversary of the death of Michael Brown at Union Square in New York, NY on August 09, 2015. Brown was killed by police officer Darren Wilson in Ferguson, Missouri, and his death set off nationwide protest against police brutality. (Photo by Cem Ozdel/Anadolu Agency/Getty Images)
TORONTO, ON- JULY 27 - Demonstrators chant 'black lives matter' during a Black Lives Matter protest that marched from Gilbert Avenue to Allen Road on Eglinton Avenue. The protest shut down the southbound Allen Road for around 30 minutes, causing traffic to reverse and exit through Lawrence Avenue. (Melissa Renwick/Toronto Star via Getty Images)
A protest sign showing and image of Ezell Ford as members of the 'Black Lives Matter' alliance stage protest outside the Los Angeles Mayor Eric Garcetti's home as they try to force him to fire LAPD Police Chief Charlie Beck, in Los Angeles, California on June 7, 2015. The alliance have renewed protests after a recent report from an LAPD watchdog determined that the August 11, 2014 officer-involved shooting death of 25-year-old Ezell Ford in South Central was justified. AFP PHOTO/ MARK RALSTON (Photo credit should read MARK RALSTON/AFP/Getty Images)
BALTIMORE, MD - MAY 03: A detail view of a man's shirt that reads 'Black Lives Matter' in front of City Hall two days after Baltimore authorities released a report on the death of Freddie Gray on May 3, 2015 in Baltimore, Maryland. Maryland Governor Larry Hogan called for a statewide 'Day of Prayer and Peace' on Sunday. (Photo by Patrick Smith/Getty Images)
BALTIMORE, MD - APRIL 25: T-shirts stating 'Black Lives Matter' are on sale for $10 each outside City Hall before a protest in honor of Freddie Gray April 25, 2015 in Baltimore, Maryland. Gray, 25, was arrested for possessing a switch blade knife April 12 outside the Gilmor Homes housing project on Baltimore's west side. According to his attorney, Gray died a week later in the hospital from a severe spinal cord injury he received while in police custody. (Photo by Mark Makela/Getty Images)
A man wears a 'Black Lives Matter' t-shirt as he demonstrates along with the group Justice League NYC and others participate in a March2Justice rally for criminal justice reform legislation to end racial profiling and demilitarize police forces outside the US Capitol in Washington, DC, April 21, 2015. Some members of the group spent a week traveling from New York City to Washington, ending with a protest rally on the National Mall. AFP PHOTO / SAUL LOEB (Photo credit should read SAUL LOEB/AFP/Getty Images)
PORTLAND, ME - APRIL 16: Black lives matter protest on the steps at Portland City Hall Thursday, April 16, 2015. (Photo by Shawn Patrick Ouellette/Portland Press Herald via Getty Images)
NORTH CHARLESTON, SC - APRIL 10: A tee shirt reading 'Stop Killing Us', and 'Black Lives Matter' are seen on a fence near the spot where Walter Scott was killed on April 4th by a North Charleston police officer on April 10, 2015 in North Charleston, South Carolina. Mr. Scott was killed by North Charleston police officer Michael T. Slager after a traffic stop and the officer now faces murder charges. (Photo by Joe Raedle/Getty Images)
WASHINGTON, USA - MARCH 14: Protestors march in silence during a Black Lives Matter protest in Saint Louis, USA on March 14, 2015. (Photo by Samuel Corum/Anadolu Agency/Getty Images)
'Black Lives Matter' is drawn on the ground in chalk as protesters demonstrate against racism in the 'Reclaim MLK' march January 19, 2015 in outside the Ferguson Police Department in Ferguson, Missouri. Critics of police treatment of minority residents in the US took part in various demonstrations across the country coinciding with the observance of Martin Luther King Jr. Day, an American federal holiday marking the influential American civil rights leader's birthday. AFP PHOTO / MICHAEL B. THOMAS (Photo credit should read Michael B. Thomas/AFP/Getty Images)
NEW YORK, UNITED STATES - 2015/01/19: Black lives matter is the message that the protesters want to bring out. Hundreds of protesters in Harlem during Martin Luther King Jr. Day demonstration gathered at Malcolm X Blvd. and Central Park North for a 'Dream4Justice' march to the United Nations, filled Foley Square in lower Manhattan and staged a die-in at Grand Central Terminal. (Photo by Geovien So/Pacific Press/LightRocket via Getty Images)
NEW YORK, UNITED STATES - 2015/01/19: A protester wears a 'Black Lives Matter' jumper in Grand Central Station. Hundreds of protesters in Harlem during Martin Luther King Jr. Day demonstration gathered at Malcolm X Blvd. and Central Park North for a 'Dream4Justice' march to the United Nations, filled Foley Square in lower Manhattan and staged a die-in at Grand Central Terminal. (Photo by Geovien So/Pacific Press/LightRocket via Getty Images)
BLOOMINGTON, MN - DECEMBER 20: Thousands of protesters from the group 'Black Lives Matter' disrupt holiday shoppers on December 20, 2014 at Mall of America in Bloomington, Minnesota. (Photo by Adam Bettcher/Getty Images)
BOSTON - DECEMBER 16: Boston High School Student Jamile Paulino was part of a Black Lives Matter protest in response to recent jury decisions. She was at gathering near Dudley Square. (Photo by Jonathan Wiggs/The Boston Globe via Getty Images)
BOSTON - DECEMBER 13: Thousands of protestors marched through the streets of Boston as part of the Black Lives Matter protest to bring attention to black justice and the recent police killings of blacks. Protestor Brian Miller throws his arms up in front of a line of State Troopers on Nashua Street. (Photo by John Tlumacki/The Boston Globe via Getty Images)
PHILADELPHIA, PA - DECEMBER 3: Ashley Thompson chanted 'Black lives matter' while joining demonstrators who gathered in Philadelphia to protest the Eric Garner grand jury decision during a Christmas Tree lighting ceremony at City Hall December 3, 2014 in Philadelphia, Pennsylvania. Organizers called for the demonstration after a grand jury in the Staten Island borough of New York City declined to indict the police officer who used a chokehold on Garner, resulting in his death. (Photo by Mark Makela/Getty Images)
Penn State student Zaniya Joe wears a piece of tape over her mouth that says 'Black Lives Matter' during a Ferguson protest organized by a group of Penn State University students on Tuesday, Dec. 2, 2014, in University Park, Pa. (Nabil K. Mark/Centre Daily Times/TNS via Getty Images)
A group of Penn State University students organized a protest in reaction to the events in Ferguson on Tuesday, Dec. 2, 2014, in University Park, Pa. The students dressed in black and laid on the floor of the HUB building for 45 minutes, many wearing signs that said 'Black Lives Matter.' (Nabil K. Mark/Centre Daily Times/TNS via Getty Images)
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Protests following police-involved deaths in Ferguson, Mo., New York and Baltimore have also cracked the veneer of unimpeachable innocence often afforded by the police badge.
But more court trials do not necessarily lead to more convictions. Retired San Francisco Bay area district attorney Tom Orloff explained it this way in The Journal: "most jurors have the idea the cops are out to do the best job they can."
Put another way, the prevailing notion in these matters is often the same; if the police use deadly force while performing their duties, it was probably necessary.
]County sheriff's deputy Daniel Willis is accused of fatally shooting Yvette Smith in February, 2014 while responding to an emergency call. Jurors are now deliberating his case.
Despite the increased number of police officers tried in court for on-duty killings, "no single officer has been convicted of murder or manslaughter this year," the WSJ reports.
Several high-profile police-involved deaths have been talked about of late, including the case of former Charleston, South Carolina police officer, Michael Slager, who was denied bond earlier this month as he waits for his murder trial to begin. Slager is accused of fatally shooting Walter Scott, an unarmed man who was running away from Slager during an encounter in April.
Six officers in Baltimore will face separate trials over the death of Freddie Gray, a man who suffered a medical emergency that severed his spine 80% at his neck while he was in police custody.