Oscar "Zeta" Acosta (April 8, 1935 – disappeared 1974) was an American attorney, politician, novelist and activist in the Chicano Movement. He had been most well known for his novels Autobiography of a Brown Buffalo (1972) and The Revolt of the Cockroach People (1973),  and his friendship with American author Hunter S. Thompson. Thompson characterised him as a heavyweight Samoan attorney, Dr. Gonzo , in his novel Fear and Loathing in Las Vegas . Acosta disappeared in 1974 throughout a trip in Mazatlan, Mexico, and is presumed dead.  
Life and career
Acosta began life in El Paso, Texas to Manuel and Juanita ( née Fierro) Acosta, from Mexico and El Paso, respectively. Oscar was the third child born but second to survive childhood. He had an older brother, Roberto, born in 1934. After the family moved to California, the children were raised in the small San Joaquin Valley rural community of Riverbank, California, near Modesto.   Acosta's dad was drafted throughout World War II.
After finishing high school, Acosta joined the U.S. Air Force. Following his discharge, Acosta worked his way through Modesto Junior College. He went on to San Francisco State University where he studied creative writing,  fitting the first member of his family to get a college education. He attended night classes at San Francisco Law School and passed the California Bar exam in 1966.  In 1967, Acosta began working locally as an antipoverty attorney for the East Oakland Legal Aid Society. 
In 1968, Acosta moved to East Los Angeles and joined the Chicano Movement as an activist attorney, defending Chicano groups and activists. He represented the Chicano 13 of the East L.A. walkouts, Rodolfo Gonzales, members of the Brown Berets, and additional residents of the East L.A. barrio. His controversial defences earned him the ire of the LAPD, who most often followed and harassed him. Local law enforcement and the FBI linked Acosta to a shadowy organisation called the Chicano Liberation Front, which claimed responsibility for numerous bombings in southern and northern California.
In 1970, Acosta ran for sheriff of Los Angeles County against Peter J. Pitchess, and received more than 100,000 votes. Throughout the campaign, he had been gaoled for two days for contempt of court. He vowed that if elected, he would do away with the Sheriff's Department as it was then constituted. Known for loud ties and a flowered attaché case with a Chicano Power sticker, Acosta lost to Pitchess' 1.3 million votes, but did beat Everett Holladay, Monterey Park Chief of Police.
In 1972, Acosta published his first novel, Autobiography of a Brown Buffalo, about a solicitor fighting for the rights of a marginalised people. It included a fictionalised account related to the murder of columnist Rubén Salazar of the Los Angeles Times . In 1973, Acosta published The Revolt of the Cockroach People , a fictionalised version of the 1970 Chicano Moratorium.
Friendship with Hunter S. Thompson
In the summer of 1967, Acosta met author Hunter S. Thompson. The latter in 1971 wrote an article on Acosta and the injustice in the barrios of East L.A. for Rolling Stone magazine, titled " Strange Rumblings in Aztlan ". This article additionally discusses the murder of Los Angeles Times columnist Rubén Salazar. When working on the article, Thompson and Acosta decided that a trip to Las Vegas, Nevada, was in order, so that they could freely discuss Salazar and racial injustice in L.A. away from any police supervision. Thompson wrote about this trip in his novel, Fear and Loathing in Las Vegas .
As Hunter Thompson wrote in his article "The Banshee Screams for Buffalo Meat" (1977), the legal department of the publisher of Fear and Loathing in Las Vegas said the book couldn't be published without clearance by Acosta, as references to him were recognizable. Acosta initially refused the clearance, saying that he had been insulted by Thompson's alteration of his race—Thompson had described him as a "300-pound Samoan." He understood, however, that inserting his real name and race would necessitate extensive rewriting and delay publication of the book, so he promised clearance provided that his name and picture would appear on the dustjacket.
In May 1974, Acosta disappeared while travelling in Mazatlán, Mexico.   His son, Marco Acosta, believes that he had been the last person to talk to his father. Acosta telephoned his son from Mazatlán, telling him that he had been "about to board a boat full of white snow." Marco is later quoted in reference to his father's disappearance: "The body was never found, but we surmise that probably, knowing the people he had been involved with, he ended up mouthing off, getting into a fight, and getting killed." 
In 1977, Thompson's investigation of Acosta's disappearance, titled "The Banshee Screams For Buffalo Meat," was published in Rolling Stone .  According to Thompson, Acosta was a powerful attorney and preacher but suffered from an addiction to amphetamines, and had a predilection for LSD. The article was Thompson's response to rumours that Acosta was alive somewhere around Miami.
Thompson wrote he believed Acosta was either murdered by drug dealers or was the victim of a political assassination.  Others have speculated that Acosta overdosed or suffered a nervous breakdown throughout his trip. 
Quotes about Acosta
Oscar wasn't into serious street-fighting, but he had been hell on wheels in a bar brawl. Any combination of a 250 lb Mexican and LSD-25 is a potentially terminal menace for anything it can reach – but when the alleged Mexican is in fact a profoundly angry Chicano solicitor with no fear at all of anything that walks on less than three legs and a de facto suicidal conviction that he'll die at the age of 33 – just like Jesus Christ – you have a serious piece of work on your hands. Especially if the bastard is already 33½ years old with a head full of Sandoz acid, a loaded .357 Magnum in his belt, a hatchet-wielding Chicano bodyguard on his elbow at all times, and a disconcerting habit of projectile vomiting geysers of pure blood off the front porch every 30 or 40 minutes, or whenever his malignant ulcer can't handle any more raw tequila.
Every century there are a few individuals who're destined to lead the weak, to hold unpopular beliefs and, most important, who're willing to die for their cause. My father's whole life was given to the fight for "the people".— Marco Acosta
One of God's own prototypes. A high-powered mutant of a few kind never even considered for mass production. Too weird to live, and too rare to die.
The film Where the Buffalo Roam (1980) loosely depicts Acosta's life and his relationship with Hunter S. Thompson. Its name is derived from Thompson's article about Acosta, "The Banshee Screams for Buffalo Meat." This title refers to Acosta's book Autobiography of a Brown Buffalo . Actor Peter Boyle portrayed Acosta, whose character is named "Carl Lazlo, Esquirem"  and Bill Murray portrayed Thompson.
Fear and Loathing in Las Vegas (1998) is a film adaptation of Thompson's novel of the same name, a fictionalised account of Thompson and Acosta's trip to Las Vegas in 1971. Benicio del Toro portrays Acosta,  referred to in the film and novel as "Dr. Gonzo", while Johnny Depp portrayed Thompson (under the alias of Raoul Duke).