Racism, as readers of Richard Wright and Chester Himes know, sometimes drives its victims homicidally mad, as in the cases of Bigger Thomas in Native Son or the anonymous sniper in Himes’s extraordinary short story ‘Prediction'. But then again, ‘mad’ may be a cowardly liberal euphemism for a radical defiance that would rather kill and die than submit to further lies and humiliation. Both stories are so unsettling because they leave the reader to divide justice by horror and then ponder the terrifying quotient.

Christopher Dorner’s 'Manifesto', the product, we’re told, of the unendurable depression that descended on the author after his dismissal from the LAPD, veers between bipolar extremes. In one section, Dorner taunts his former comrades in sneering acronyms that boast his expertise: 'Your APC are defunct... My POA is always POI.' But the rant is followed by sentimental acknowledgments to friends and several pages of fan notes to eclectic heroes who include Hillary Clinton (his first choice for president in 2016), Chris Christie (his second choice), Dave Brubeck, General Petraeus and Ellen DeGeneres. He’s also a passionate advocate (and argument for) gun control.

Perhaps his brain synapses have been misfiring for a long time, but the core of Dorner’s Manifesto is a coherent account of how a police Explorer Scout realised his life’s dream as a LAPD rookie and then had his reputation and career destroyed for being an honest cop. He debunks the myth – propagated by the LA Times, Mayor Villaraigosa, and most of the liberal establishment – that thanks to Saint Bratton a kinder, gentler and more diverse LAPD now protects and serves Los Angeles.

Indeed Dorner’s eye-witness account of routine sadism, racism and conspiracy in the department is totally in line with its historical institutional culture and was inadvertently fact-checked by the LAPD’s wild shooting of two innocent women and Chief Beck’s kneejerk exculpation of the officers involved. (Those who think that there are no more Rodney Kings should look carefully at the case of the LAPD patrol woman who killed a mentally ill woman last summer by stomping on her genitals.)

If Dorner were standing on a skyscraper ledge or holding Rupert Murdoch hostage, the world might pay more attention to the injustices that he chronicles. But he has instead chosen, as he puts it, to make his enemies’ homes his 'war space' and their families his targets. Thus his spree began not with his Barrett .50 aimed at LAPD headquarters, but with the murder of a cop’s daughter and her fiancé.

Outlaw heroes are not this pitiless and there is no warrior honour in killing helpless family members. So who is Dorner? He will undoubtedly be buried in multiple coffins by competing theories and explanations. Some will fit him for serial killer lunatic, while on the AM dial he’ll be denounced as liberalism’s Timothy McVeigh. Obama will be blamed.

But I’m haunted by an eerie precedent to Dorner’s story: the legend of Mark Essex. He was a monster in the same sense as Dorner: his rage at injustice and humiliation became an annihilating violence.

A young Black navy veteran with almost no formal weapons training, Essex boldly attacked the headquarters of the New Orleans Police Department on New Year's Eve, 1972. After killing a black police cadet and wounding a white lieutenant, Essex escaped to a nearby warehouse where he ambushed a K-9 unit and killed another cop. For a week he eluded a vast manhunt before suddenly reappearing in the Howard Johnson Hotel across the street from City Hall. Going floor to floor, always warning the housekeepers to flee, he shot down hotel managers and white guests, setting rooms afire as he climbed toward the roof.

The New Orleans police rushed the hotel, but Essex with uncanny accuracy shot cops off fire ladders, mowed them down in stairwells and killed them as they stepped out of elevators or got out of their cars in the streets below. By nightfall on 7 January 1973, Essex – now bunkered on the roof of Howard Johnson – had militarily defeated the entire New Orleans Police Department. He had shot ten police officers (five dead, including a deputy chief) and eleven white civilians (four dead) while withstanding thousands of rounds of police fire without a wound. Ultimately a marine helicopter was brought in and after taking numerous hits from Essex in three runs at the hotel, a police sharpshooter killed the one-man black liberation army. When the coroner received what remained of Essex he counted 200 bullet wounds.

In his superb reconstruction of this New Orleans Armageddon (A Terrible Thunder: The Story of the New Orleans Sniper) first published in 1978, Peter Hernon anticipates some of the key questions that may confront Dorner’s biographer. Essex grew up in Emporia, Kansas, the child of a blue-collar black family in an almost all-white town. (Dorner emphasises that he was the only black child in his classes until middle school.) Hernon finds nothing traumatic or disturbed in Essex’s life until he joins the navy in the late 1960s and trains in San Diego as a dental technician with the hope of someday going to dental school. The white navy dentist whom Essex assisted recalls him rather fondly to Hernon as a cheerful 19-year-old from Kansas.

But the navy in 1969 is anything but cheerful. In the white ranks there’s seething hostility against promotion of blacks and race riots have erupted on the flight decks of the big carriers. Many black sailors, as well as a minority of whites, are alienated by the war in Vietnam and the Nixon backlash at home. Hernon is stationed at a small naval base in Imperial Beach (last exit before Tijuana and the site of the hugely subversive and accordingly short-lived HBO series, John from Cincinnati) where he and other black sailors are tormented by racist CPOs. (Hernon quotes one as loudly proclaiming: 'God, it must have been beautiful twenty or thirty years ago. When a nigger went to sea it was below the decks, in the galley.') Finally, after one slur too many, Essex decks a white sailor.

He’s doomed. Like Bob Jones, the black shipyard worker in Himes’s ferocious 1945 novel If He Hollers Let Him Go, a single misstep and his life spirals downward. In the face of unfair punishments and continuing abuse, Essex loses faith in a naval career. He goes AWOL and is kicked out of the service. Unlike Dorner however, Essex is able to place injustice in a political framework; there are plenty of radical cats in the navy in 1970 and he gravitates towards the Black Panthers, first in New York and then in New Orleans. Police attacks on the Desire projects and the killing of local activists convince Essex that it is time for war. Hernon is very clear, however, that this was a solo project, ‘revolutionary suicide’ in the terminology of the time. But Essex doesn’t die entirely alone. As he kills cops from the rooftop of the Howard Johnson, young Black people in the street cheer him.

Does anyone cheer Dorner?