Police officers routinely display selfless, life-saving heroism. That was apparent last Saturday night at a mall in St. Cloud, Minnesota, where off-duty officer Jason Falconer confronted and shot to death Dahir Adan after the 22-year-old had stabbed 10 people. Falconer was widely and deservedly praised for acting quickly to save lives.

But one can revere this heroism while still having profound reservations about a police culture that seems far too tolerant of – and too quick to defend – the use of lethal force against unarmed people, often African-Americans.

Another example came last Friday in Tulsa, Oklahoma, when police Officer Betty Shelby fatally shot Terence Crutcher, 40, who was unarmed and standing by his vehicle. In videos released Monday, there is no evidence that Crutcher was behaving in a threatening way. (Shelby will be charged with first-degree manslaughter in the shooting, the Tulsa County district attorney announced Thursday.)

It was impossible not to think of the wrenching videos of Alton Sterling and Philando Castile, men killed by police in Minnesota and Louisiana, respectively, in early July. The reaction of Crutcher’s twin sister, Tiffany Crutcher, to video of an officer calling him a “bad dude” before he was shot was unforgettable.

“The big bad dude was my twin brother. That big bad dude was a father,” she said. “That big bad dude was a son. That big bad dude was enrolled at Tulsa Community College, just wanting to make us proud. That big bad dude loved God. That big bad dude was at church singing with all of his flaws, every week. That big bad dude, that’s who he was.”

Now he’s dead – for no reason at all.