Deonnah Conway holds candles during a March 23 protest over the police shooting of Stephon Clark in Sacramento. (Bob Strong/Reuters)

“Gun, gun, gun.” That was the warning shouted out seconds before Stephon Clark was shot and killed by Sacramento police in his grandparents’ back yard. But Mr. Clark didn’t have a gun. The 22-year-old man, it was quickly discovered, had been holding only a cellphone. Days later, another black man — also unarmed — was fatally shot by police in Houston. Danny Ray Thomas, 34, was standing in a busy intersection with his pants around his ankles when he was shot.

Why are these men dead? Tragically, that is not a new question. It was asked in 1999 after Amadou Diallo, 22, died in a hail of bullets from New York police who mistakenly thought he had a gun; in 2006 after Sean Bell, 23, was fatally shot by police as he sat in a car after leaving his bachelor party in New York; in 2014 after 12-year-old Tamir Rice was shot by police as he played with a toy gun in a Cleveland park; in 2015 after Walter Scott, 50, was fatally shot as he ran away from a traffic stop in North Charleston, S.C.; in 2016 after Gregory Gunn, 58, was shot by a police officer in Montgomery, Ala., as he was knocking on a neighbor’s window for help; and again when Philando Castile, 32, was shot after being pulled over by police in a suburb of St. Paul, Minn.

The deaths of Mr. Clark on March 18 and Mr. Thomas on March 22 are under investigation. Both were captured on videos that have been made public, raising issues that bear scrutiny. It took only seconds for Sacramento officers — responding to a call about car break-ins — to start shooting, reportedly firing as many as 20 times, after encountering Mr. Clark in the dark. Why didn’t they identify themselves as police? Why did police mute the audio on their body cameras after Mr. Clark was shot? In the case of Mr. Thomas, why was lethal force needed to deal with an unarmed man with his pants down in the middle of the day? Mr. Thomas’s family said he was struggling with the deaths of his two children (allegedly drowned by their mother in 2016). Was this an instance, as is often the case with police shootings, of police not trained to deal with people suffering from mental illness?

A Post database of fatal shootings by on-duty police shows 244 people have been shot and killed by police so far this year, about the same pace of three fatal shootings per day since 2015. The victims are disproportionately minorities. But the issue, as The Post’s Wesley Lowery recently wrote, has receded from the national political conversation. Under the Obama administration, it was a priority, but Attorney General Jeff Sessions has shown no interest in police reform and President Trump himself once advised a police audience “Don’t be too nice” taking “thugs” into custody.

Mr. Clark and Mr. Brown should not be dead. That their race likely was a factor in their shootings needs to be talked about. And action is needed to prevent more senseless deaths.