Air Force veteran Anthony Hill was the latest victim, who was killed by a white officer in Atlanta, Georgia on Monday.
The 27-year-old Hill was reportedly suffering from a mental illness.
The officer, who was responding to reports of a suspicious person, fired two shots and killed Hill, who was running around in an apartment complex naked.
The shooter, white police officer Robert Olsen, has been placed on administrative leave.
"The man he was confronting, Anthony Hill, was completely unarmed so it was completely within the realm of possibility to use a non-lethal force of de-escalation, and he chose to fire two bullets at point-blank range into his heart," one witness said.
The second victim was unarmed black man, Naeschylus Vinzant, who was killed by police on Friday in Aurora, Colorado.
According to police, Vinzant was suspected of robbery and kidnapping.
The police officer, who killed the 37-year-old Vinzant, has also been placed on administrative leave.
Police officers did not learn Vinzant was unarmed until after he was shot dead, Aurora Police Commander Paul O’Keefe said.
The third victim was unarmed black teenager Tony Robinson, who was shot dead by police officer Matt Kenny in an apartment in Madison, Wisconsin.
The shooting death of Robinson has drawn comparisons to the fatal shooting of 18-year-old Michael Brown, another unarmed black, in Ferguson, Missouri, last year.
Police brutality as well as the racial profiling of minorities by US law enforcement agencies has become a major concern in the United States.
The killing of several unarmed black men by white police officers in recent months and decisions by grand juries not to indict the officers triggered large-scale protests across the US.
There is also widespread racial disparity in the US criminal justice system. According to a study by the Sentencing Project research group, one in three black males, are likely to be sentenced to prison sometime during their life. The figure for white men is one in 17.
In an interview with Press TV, American political commentator Mickey Z. said that white supremacy still rules in the United States and it is even worse than fifty years ago.
He made the comments while people in the US marked the 50th anniversary of “Bloody Sunday” civil rights march.
The demonstrators on Sunday commemorated the march from Selma to Montgomery that resulted in a bloody confrontation between police and peaceful protesters on March 7, 1965.
In 1965, Alabama police beat protesters that helped bring about the 1965 Voting Rights Act, a landmark achievement of the 1960s American Civil Rights Movement.
The march “demonstrates this country’s love of denial because we mark anniversaries like this as if they are relics of the past, while white supremacy still rules and is perhaps more insidious than ever,” Mickey Z. said.
“Fifty years later, we still have to be reminded that black lives matter,” he added.
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