When Chicago police officer Jason Van Dyke testified in his own defense about why he shot Laquan McDonald, killing him with 16 shots, Van Dyke said he felt that his life was threatened, based off a look on the African-American teenager’s face.

“His eyes were just bugging out of his head,” said Van Dyke. “He had just these huge white eyes just staring right through me.”

This is the Black Boogeyman defense that has been given in testimony after testimony from police officers in court when testifying about why they shot or killed an African American they suspected was up to no good. And usually it works, but in this case it did not. Van Dyke was found guilty Friday of second-degree murder of Laquan McDonald, and was also handed guilty verdicts for aggravated battery for each of the 16 shots that he fired into McDonald’s body on October 20, 2014. That’s six to 30 years for each of those counts, not including the years he could get for the second-degree murder charge.

In the past when police officers have taken the stand to describe what was going through their heads when they decided to pull the trigger on often-unarmed black suspects (McDonald had a small knife in his hand when Van Dyke killed him), they usually recount something about the suspect’s demeanor or behavior—their facial expressions, size, stature, or something the suspect is smoking—that made them afraid for their life:

• When Ferguson police officer Darren Wilson testified about Michael Brown, the unarmed teenager he shot and killed, Wilson said that Brown  “was just staring at me, almost like to intimidate me or to overpower me,” and that when he grabbed Brown “it felt like a five-year-old holding onto Hulk Hogan.”
• Cleveland police officer Timothy Loehmann said in police interviews that he thought the 12-year-old black child Tamir Rice looked more like an 18-year-old when he pulled up in his squad car and shot Rice in split seconds, killing him.
• Officer Jeronimo Yanez said after killing the African-American man Philando Castile in Falcon Heights, Minnesota, outside of St. Paul, that it was dark and he could “barely see” but because he smelled cannabis smoke he thought that Castile had a gun and wanted to kill him. Said Yanez:

“I thought if he’s, if he has the, the guts and the audacity to smoke marijuana in front of the five year old girl and risk her lungs and risk her life by giving her secondhand smoke and the front seat passenger doing the same thing then what, what care does he give about me. And, I let off the rounds and then after the rounds were off, the little girls was screaming.”

• Baton Rouge police officer Blane Salamoni said after killing the African-American man Alton Sterling that, “From the minute I walked up I was in fear of my life, because I knew there was a high probability that he was armed with a firearm and he was trying to get it.” Salamoni said that he was cursing at Sterling while he shot him because profanity is “100 percent used to gain compliance from the suspect,” in high stress situations and that, “Obviously a lot of thugs and people on drugs curse.” His partner Officer Howie Lake II called Sterling an idiot after Salamoni shot him because:

“I called him a f—ing idiot because it didn’t have to go that way. I was amped up on adrenaline because he made it go that way. Sterling could have just surrendered his hands and went back to jail.”

White Americans, particularly those in law enforcement, have invoked the “bulging eyes,” large body size, the use of cannabis, and the “thug” appearance of African Americans since at least the late 19th and early 20th century to describe black men as threatening. These brute tropes that have been used in racist movies like “Birth of a Nation” and other Ku Klux Klan propaganda in campaigns that claimed America as a country under siege by menacing African Americans roaming the landscape. These were also ways to scare people during the so-called “Great Migrations,” when African Americans were migrating into northern cities en masse.

A recent study from researchers CalvinJohn Smiley and David Fakunle investigated how language has been used to describe African Americans who were killed by police between July 2014 and April 2015 and found:

Specifically, there is a demonizing process that happens to unarmed Black men posthumously. Unlike earlier Black icons and figures, such as Dr. Martin Luther King, Jr. and Malcolm X, that were vilified while alive and then sanitized in death to be repackaged as an acceptable part of the United States historical narrative, these men are portrayed as thugs and criminals to seemingly justify their deaths while simultaneously shifting blame away from law enforcement.

This was language Chicago police officer Van Dyke relied on to describe McDonald, and why not? It has worked so effectively throughout history for police officers, especially those in Chicago. In 2015, 95 percent of police officers involved in shootings in cities across America were not even charged with a crime, let alone convicted, according to Mapping Police Violence.

Van Dyke is now the first police officer in Chicago to be found guilty of murder for killing a civilian in decades. The fact that this comes at the expense of an African-American life seems to hint that justice is turning a corner, at least in Chicago. The verdict is still out on that, but at least the message has been sent that cops can no longer rely on racist descriptions of African Americans to save their own lives.