(CNN) A civil rights attorney who represents the families of black men slain by police states it plainly and unapologetically.

The white man accused of committing "a mass shooting in Florida (was) not shot once, but a young black man holding a cellphone is shot 20 times," Benjamin Crump said of the unarmed father gunned down this month by Sacramento, California, police who say they thought he had a gun.

Crump went on.

"A young man who was bombing homes in Austin, Texas, police followed him for hours. He wasn't shot once," he said, referring to the bomber, who was white. "But an unarmed black man holding a cellphone was shot 20 times."

Observations like these have resurfaced with fervor after a series of incidents across the country this month -- including the shooting death of Stephon Clark in Sacramento -- again raised questions about unequal treatment of people of color by police.

Years after the emergence of Black Lives Matter , a social movement borne of the shooting death in Florida of 17-year-old Trayvon Martin , there is still a widely held perception of law enforcement's racial animus toward people of color, especially in the communities they're sworn to serve.

"These examples are benchmarks in terms of understanding that if you think there's been progress, ... we have a long way to go before law enforcement in America is doing its jobs as it should be done," Jeffrey Robinson, director of the Trone Center for Justice and Equality at the American Civil Liberties Union, said of half a dozen cases that gained national attention in recent weeks.

"It's a very difficult thing to admit that race makes a difference in the criminal justice system," he said, "because if we admit that's true, it says some pretty ugly things about ourselves as a nation."

'Patterns are stark and disturbing'

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In Baton Rouge, Louisiana, this week, Louisiana Attorney General Jeff Landry announced that no charges would be filed against two police officers in the 2016 shooting death of Alton Sterling. The African-American man was selling CDs outside a store when officers, responding to a call about a man with a gun, pinned him to the ground and shot him. The incident, which investigators determined was justified, led to protests.

The Southern Poverty Law Center reacted to the decision via Twitter: "The final moments of #AltonSterling's life looked less like a police stop and more like a public execution."

The final moments of #AltonSterling's life looked less like a police stop and more like a public execution.



Louisiana's decision not to bring criminal charges against Baton Rouge police officers in his death raises serious questions.https://t.co/G2nZR6jYEG — Southern Poverty Law Center (@splcenter) March 27, 2018

"We must know that law enforcement values the lives of all the people they are sworn to protect and serve," SPLC President Richard Cohen said in a statement.

In Houston, authorities launched an investigation into the shooting of Danny Ray Thomas, 34, who died last week from single gunshot wound fired by a sheriff's deputy.

The Fair Punishment Project, an advocacy group affiliated with Harvard's Criminal Justice Institute, tweeted : "It took only 17 seconds from the moment a Harris County sheriff's deputy ordered Danny Ray Thomas to get on the ground to the moment he fired a bullet that killed Thomas -- who was unarmed. 17 seconds."

Decynthia Clements

In Elgin, Illinois, a 34-year-old woman named Decynthia Clements, whom police believed was suicidal and possibly armed with a knife, was fatally shot by a police officer. Police this week planned to release 30 hours of police body-camera footage in an effort to be transparent.

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In western North Carolina, assault charges were announced this month against a former police officer, Christopher Hickman, who was captured on body-camera video hitting and using a Taser on a black man suspected last summer of jaywalking.

"The patterns are stark and disturbing," Robinson said. "When the suspect is white, we ... tend to be able to talk about their humanity in a completely different way than when the suspect is black."

'A young white man who terrorizes a city'

Interim Austin Police Chief Brian Manley, who is white, took heat this month for how he described a 25-minute video in which Mark Anthony Conditt, whose handcrafted bombs killed two people and wounded five in Texas, confessed to building the devices. Conditt blew himself up last week as police moved in.

"It is the outcry of a very challenged young man talking about challenges in his life that led him to this point," the interim chief said of the confession.

Sherrilyn Ifill, president and director-counsel of the NAACP Legal Defense and Educational Fund, on Twitter called out the chief for his description of "a young white man who terrorizes a city."

"I believe passionately in acknowledging the humanity of those who commit even terrible crimes," she said.

"Reading this police chief's empathy for this young white man highlights the awfulness -- the plain awfulness -- of the persistent refusal to extend this empathy to young black people."

"Remember how they talked about innocent black children," like Trayvon Martin, Tamir Rice and Freddie Gray, Ifill wrote.

The first blasts Conditt orchestrated -- one on March 2 and two more on March 12 -- killed or wounded three African-Americans and one Hispanic woman. They occurred in parts of east Austin where most residents are minorities. Some there expressed fear the attacks might have been racially motivated, a theory police never seemed to take seriously, according to residents and community activists.

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The first explosion killed Anthony Stephan House, 39, who the police initially suggested may have set off the bomb himself; the second killed Draylen Mason, 17, a gifted music student.

Manley has defended his downplaying of the first bombing, saying investigators initially believed it came in retaliation for police having taken "a significant amount of cash out of a drug stash house" a few days earlier on the same street.

But for longtime black and Latino residents of the largely segregated city, the bombings will always be considered acts of terror, said Eric Tang, an associate professor at the University of Texas at Austin.

"No matter what the motive might have been, it remains that the black and brown community on the East Side felt terrorized," Tang said. "What comes to mind when you hear a bomb has gone off in a Southern city?"

The fears of residents did not appear to register quickly enough with the leadership of a city that has long billed itself as tolerant and progressive, he said.

"This wasn't being addressed in any direct way by authorities even if they couldn't prove that early that there was a hate crime motive," Tang said. "It seems worth it to me that they would acknowledge the disparate impact it would have on a community that has historically faced racial violence and presently faces racial inequality."

Manley this week leaned in that direction, describing the bombings as "domestic terrorism" and Conditt as a "terrorist."

"I actually agree now that he was a domestic terrorist for what he did to us," Manley said during a panel discussion broadcast by KUT-FM. "This is a distinction I wanted to make."

Manley talked about the bomber's impact on the community but did not single out the effect on blacks or Latinos.

'We can be legally killed at any moment'

Meantime, the streets of California's capital have been reeling for days with outraged residents demanding accountability for the shooting death of Stephon Clark.

Police have said Clark had a gun, but only a cellphone was found near his body. Some want the two officers involved in chasing and killing Clark -- in response to reports of petty vandalism -- to be fired and prosecuted. The officers -- one of whom is black -- have been placed on administrative leave as California's attorney general investigates.

"#StephonClark's murder reminds us we live in a country where we can be legally killed at any moment for any reason and there is no real system in place to help (or protect) us," tweeted Symone Sanders, a CNN political commentator who was national press secretary for Bernie Sanders' Democratic presidential campaign.

"It seems as though that when we have suspects or people who are engaged in situations with police officers that are a little more 'melanated' than some of our counterparts, they seem to not make it out of the situations alive," Symone Sanders later told CNN, referring to people with brown or black skin.

"They do not get due process. They do not get to go through the process, and they're not given the benefit of being innocent until proven guilty."

#StephonClark's murder reminds us we live in a country where we can be legally killed at any moment for any reason and there is no real system in place to help (or protect) us. — Symone D. Sanders (@SymoneDSanders) March 29, 2018

At a city council meeting this week, Clark's brother, Stevante Clark, told the crowd, "The mayor and the city of Sacramento has failed all of you." He cited entrenched ills such as high rents, poverty and gang violence.

Indeed, Robinson of the ACLU said law enforcement's use of "extreme violence against people of color goes back to my parents' generation to their parents' generation and to their parents' generation."

"But people are beginning to discuss these issues in a way that is different than I've seen in my entire life," said Robinson, 61, who was born and raised in Memphis.

"More people are becoming more aware of these kinds of hypocrisies in our criminal justice system," he said. "If there is hope that I find, it's that these stories are being discussed in a much broader way."

In Washington, White House press secretary Sarah Sanders this week called the fatal police shootings of Sterling and Clark "a local matter."

"Certainly a terrible incident," Sanders said of both cases. "This is something that is a local matter and that's something that we feel should be left up to the local authorities at this point in time."

But Crump sees it differently.

"This is a national issue. These are our children being killed in every city," the attorney said. "The lists goes on and on. We've done so many of these interviews, and yet for whatever reason, there's an intellectual justification to always exonerate the police when they kill black people. We have to change that."