The number of American police officers charged with murder has tripled in 2015, a sharp increase attributed to more video evidence.
According to a new report by CBS, so far this year 15 police officers have been charged with manslaughter with 9 of the cases recorded on video.
The figure is three times the annual average of less than 5 officers that were charged in the preceding years.
"If you take the cases with the video away, you are left with what we would expect to see over the past 10 years -- about five cases," said Philip Stinson, a criminologist at the Bowling Green State University. "You have to wonder if there would have been charges if there wasn't video evidence."
The importance of video evidence was underscored last week when footage of a black teenager’s fatal shooting by a white Chicago officer was made public.
The graphic video showed the shooting of 17-year-old Laquan McDonald by officer Jason Van Dyke on October 2014.
The video sparked public outrage and prompted President Barack Obama to address the issue on TV. Obama said he was “disturbed” by the incident.
After being charged with first-degree murder last week, Van Dyke became the 15th officer in the country to face such charges in 2015. The officer now faces up to 20 years in prison.
Earlier in May, 6 police officers were indicted on charges connected to the video-taped death of African-American Freddie Gray in police custody.
Gray, 25, died on April 19, one week after he was arrested by police officers who appeared to roughly lift him in handcuffs from the ground and drag him to the back of a police van, where he suffered a fatal injury to his spine.
Over the last decade, the US law-enforcement agencies have taped about 1,000 fatal shootings by on-duty police officers.
Nearly 900 people have been killed by police since the beginning of 2015, an activist group known as Killed by Police announced in mid-October.