William “Roddie” Bryan’s video of Gregory and Travis McMichael shooting Ahmaud Arbery is not the first image Americans have seen of whites killing African-Americans. In recent years, videos made by witnesses on mobile phones or body cameras worn by law-enforcement officers have circulated via social media and news sites. Like Bryan, the makers of these images have sometimes also been participants, and in this way, these videos have a great deal in common with lynching photographs made regularly from the 1880s through the 1930s. What is different, however, is that Bryan has been arrested and charged with felony murder because of his participation. For what may be the first time, these kinds of images are actually being used as evidence to charge their maker with alleged crimes.The history of lynching is essential to the conversation about Bryan’s complicity. One problem is that too many Americans, if they have heard the term much at all, have a limited and narrow understanding of lynchings as hangings conducted by mobs. Yet, as Ida B. Wells, the African-American journalist and activist, and the National Association for the Advancement of Coloured People long ago made clear, lynchers have killed their victims in a variety of ways. While anti-lynching activists in the first half of the 20th century never completely agreed on a definition, three characteristics were usually required to label an act of violence a lynching: the victim had to die, two or in some cases three or more people had to participate in the murder and the killers had to operate under the pretext of delivering justice or upholding tradition. Most lynchings have been carried out by small groups of accomplices acting in relative private by perpetrators who believe they are justified because they are somehow upholding the social order.Arbery’s killing allegedly fits these characteristics that make a murder a lynching. Travis and Gregory McMichael and Bryan were at the scene when Arbery died and their public statements as well as police reports and other documents suggest they understood their acts as just. In a letter to the Glynn County Police Department explaining why he did not recommend that they press charges, District Attorney George Barnhill described the McMichaels as “following, in ‘hot pursuit’, a burglary suspect, with solid first-hand probable cause, in their neighbourhood, and asking/ telling him to stop”.Through his lawyer, Bryan has said that he was simply trying to get a good picture in case the suspect got away.Likewise, the lynching images that survive are powerful illustrations of racial violence and its enablers. Most depict a type of crime I have labelled “spectacle lynchings”.In these grisly affairs, white mobs tortured and killed African-Americans in front of large crowds, and participants and witnesses collected and purchased what journalist H.L. Mencken called “souvenirs”, pieces of the corpse, links of the chain or segments of the rope and even bits of wood chopped off hanging trees or scaffolds. Enterprising local photographers took advantage of this market and shot, quickly printed and sold photographs as postcards to people who attended these murders.In an important early example, one of the men who lynched Henry Smith in Paris, Texas, in 1893 wrote up a narrative of the crime and printed it in a pamphlet along with multiple photographs of the lynching. In the killing of Jesse Washington in Waco, Texas, in 1916, lynching photographs took the form of a series that functioned much like a film. Because a white woman working undercover for the NAACP managed to buy a complete set, the surviving evidence depicts Washington and his killers before, during and after his killing. Unlike these examples, most lynching photographs do not document the actual murder but its aftermath, killers and spectators — the line between these roles was always a blurry one — posing with their dead victims.Although it is possible to identify people in these images, law-enforcement officials do not seem to have considered them as documents that offered clear evidence of crimes. In many lynching photographs, like pictures made of the 1899 lynching of Sam Hose near Newnan, Georgia, or the 1935 lynching of Ruben Stacey in Fort Lauderdale, Florida, the faces of participants and spectators are clearly visible. Yet coroner’s inquests and other investigations, when they did occur, almost always ruled that lynching victims died “at the hands of a person or persons unknown”.Sometimes law-enforcement officials did more than cover up these acts of violence. In some cases, law enforcement made it easy for lynchers to take men out of jails. In other cases, they participated more directly. In the Jesse Washington lynching, the NAACP found evidence that the sheriff knew about the lynching before it occurred. In exchange for a payment, he tipped off the photographer, telling him which building to set up in to get the best view.Such images of racial violence have long played a role in justifying white supremacy. What appeared to some viewers concrete evidence of injustice looked to other viewers like evidence of justice done, proof that sometimes “criminals” — including those not charged or convicted of any crime — got what they deserved.Yet lynching photographs were not just evidence that acts of violence had been committed. They were also artefacts that perpetuated the violence of the acts they depicted. No matter the perspective of the viewer, these images reinforced white supremacy by suggesting that African-Americans had no rights that white people were required to respect. They taught viewers that whites were people who could kill African-Americans in the open, with impunity, even when the murderers and their accomplices were identifiable in photographs. In this sense, the people who made these images always participated in the events they captured, whether they laid a hand on the victims or not. Reproducing and circulating these images continued to produce new spectators long after the lynching occurred. The existence of pictures transformed every lynching into a spectacle.The investigation into Bryan’s video and his and his neighbours’ alleged complicity in the murder of Ahmaud Arbery needs to grapple with this history of lynching images and the role they have always played in amplifying the power of the violence they depict. Across almost a century and a half, white men have killed African-Americans, and gotten away with it, even when they have been caught on camera. It remains to be seen whether anyone will be held accountable in Arbery’s murder. Historically, pictures have held little power in contexts in which law enforcement officials do not see lynching and other forms of white vigilantism as a crime. Yet through their deep connections to these crimes, they have also possessed the terrifying power to turn us all into spectators.• Grace Elizabeth Hale is a historian of 20th century US culture and a professor of history and American studies at the University of Virginia