Troy Davis, the death row inmate whose guilt in the 1989 murder of Officer Mark Allen MacPhail has been seriously called into doubt, was executed by lethal injection at 11:08 p.m. ET after the Supreme Court refused to stay his execution. With his last words, he reportedly maintained his innocence to the McPhail family.

The high court's ruling landed at 10:20, three hours and twenty minutes after Davis had been scheduled for death—an agonizing wait for spectators, and no doubt a special kind of suspended, Schroedinger's-cat hell for Davis and his family (above, his sister and nephew). Riot cops showed up outside the prison in the hundreds; helicopters buzzed overhead. Protestors sang and chanted. And now, finally and for sure: Troy Davis is dead.

In 1991, Davis was convicted of murdering Officer Mark Allen MacPhail, largely on the testimony of nine witnesses. Since then, seven of those witnesses have changed their stories, some implicating another man. Many said that they'd been intimidated or otherwise pressured by police to testify. Furthermore, there's no DNA or fingerprint evidence linking Davis to McPhail's murder; no weapon has ever been found; and Davis has consistently maintained his innocence throughout. Tonight was the fourth time he'd been scheduled for execution.

Reasonable people can disagree about Troy Davis' innocence. That is the point. Because once you allow that—once you admit that a reasonable person might think him innocent—you have to ask: what if you're wrong? There are no "backsies" with the death penalty. Victor Hugo called it "the irrevocable, the irreparable and the indissoluble." It's the most awful power imaginable, and we've invested an imperfect system—a racist, classist system—with it. We should be terrified at the possibility that an innocent person might die. We should be horrified that it probably happened tonight.

Before he died, Troy Davis reportedly told the MacPhail family, "I did not personally kill your son, father, brother. I am innocent." His last words were to his executioners: "May God have mercy on your souls. May God bless your souls."

Davis, by the way, was not the only inmate who was set to die tonight. White supremacist Lawrence Russell Brewer, who killed James Byrd Jr. by dragging him behind his pickup truck, was killed by lethal injection in Huntsville, Texas, at 6:21 p.m. CT.

[image of Davis' sister and nephew via AP]