Two years ago a National Public Radio investigation showed that, since 2015, at least 135 unarmed Black men and women nationwide were fatally shot by police officers. At least 75 percent of the police officers were white.

Two years later, the steady drum of Black people being killed at the hands of law enforcement employees continues. While many of the killings continue to be by gunfire, ripping apart victims’ hearts, lungs and livers, many Black lives increasingly are left lifeless by the arms, fists and knees of police officers, sheriff’s deputies and others hired to uphold the law.

Yet the color of the officers charged with killing Black men and women seems to have changed.

Just two months ago in mid-January, we watched a video of Tyre Nichols, 29, being brutalized by police in Memphis, Tenn. Mr. Nichols, who is said to have suffered with mental health challenges, barely survived the beating. He died a few days later.

His accusers—men in blue—are all Black.

Two weeks ago the horror happened again at Central State Hospital in Dinwiddie County, about 35 miles from Richmond. Henrico County sheriff’s deputies were arrested for murdering 28-year-old Irvo Otieno, another Black man who is said to have had mental health challenges, too.

Most of his accusers, men and women who vow to uphold the law, are Black.

What to make of this is unclear. Black-on-Black crime has long existed in our communities and countless studies have examined this heartbreaking phenomena to no end. But recent incidents of Black men and women in uniform who commit cowardly acts of brutality by piling on and choking to death victims such as Mr. Otieno as he lay handcuffed and with his feet shackled is not only tragic but senseless.

Ben Crump, the civil rights attorney whom we saw in January stand with Tyre Nichols’ family stood with Mr. Otieno’s family two days ago at Richmond’s First Baptist Church of South Richmondand in Dinwiddie County.

If anyone doubted the gravity of this latest act of violence against a defenseless Black man, Mr. Crump’s presence made this vicious crime all the more clear. Mr. Crump, who also represented the family of George Floyd, told the Associated Press that Mr. Otieno’s treatment has close parallels with Mr. Floyd’s killing in police custody in Minneapolis in 2020.

NAACP President and CEO Derrick Johnson made a similar comparison in a statement Tuesday.

“Police are simply not a substitute for compassionate and informed mental health professionals,” Mr. Johnson said. “Rather than neglecting and criminalizing the Black community, we need action to make sure no one experiences or witnesses this kind of violence at the hands of law enforcement ever again.”

Mr. Otieno’s family has equated his treatment to torture and are calling for the U.S. Justice Department to intervene. Another family attorney, Mark Krudys, said defense attorneys are making excuses about what happened at Central State, including assertions that Mr. Otieno “was combative.”

“He was just trying to breathe,” Mr. Krudys said. “That’s all he was trying to do.”