Citing a gruesome series of killings in Los Angeles in which one victim was dismembered and whose heart was cut out, a federal grand jury has indicted 22 alleged members or associates of the notorious MS-13 gang on charges that include racketeering and murder.Five of the seven killings outlined in a new indictment involved the victims\u2019 bodies being dumped in Angeles National Forest, according to court documents.The 78-page grand jury indictment says 22 alleged members and associates of the MS-13 Fulton clique, based in the Los Angeles suburbs of the San Fernando Valley, engaged in common street gang business: narcotics sales, robberies, burglaries and extortion schemes.But the indictment also details how those charged also used horrific violence to control members, protect territory and intimidate rivals.The case is the culmination of a two-year investigation by the FBI, Los Angeles Police Department and Los Angeles County Sheriff\u2019s Department.The U.S. attorney for the Central District of California, Nicola T. Hanna, and other officials are expected to provide additional details at a news conference Tuesday morning.Formed in Los Angeles in the mid-1980s, MS-13, also known as Mara Salvatrucha, has a footprint in at least 10 states, including California, New York, Virginia, Maryland and Texas, as well as several Central American countries, including El Salvador, Honduras, Mexico and Guatemala.Fulton is one of at least 20 subsets, or cliques, of the gang operating around Los Angeles, and federal prosecutors said it modeled itself after a subset of the gang in El Salvador known as \u201c503.\u201d That group broke away, the indictment alleges, and became more violent after the El Salvadoran government tried to quell violence by arranging a secret truce with older MS-13 leaders.Salvadoran MS-13 members who were recent arrivals to Los Angeles often identified with the 503 group and joined with Fulton members to carry out the slayings detailed in the indictment, the court papers allege.In Los Angeles beginning in 2017, MS-13 members who identified with the 503 group had been required to kill a gang rival or "someone perceived to be adverse to MS-13" in order to be initiated, the indictment says.The indictment also suggests that the Fulton group operated differently from other MS-13 cliques in Los Angeles."MS-13 in Los Angeles was distinct from MS-13 cliques in other parts of the country, because in Los Angeles, MS-13 had to pay extortionate rent payments to the Mexican Mafia, to which MS-13 swore fealty," the indictment states.Among the seven murders at the center of the 12-count indictment was the killing of an individual identified as "J.S.," who federal prosecutors said was choked and dismembered in March 2017 for crossing out MS-13 graffiti.One alleged gang member "carved out J.S.'s heart," and others "threw J.S.'s body parts into a canyon" in the Angeles Forest, the indictment says.A month later, another victim, identified as G.B., was struck on the back of the head with a pistol and hacked to death with a machete, according to the court filing. His body was found close to the first dump site in the forest.Federal prosecutors said some of the MS-13 gang members suspected G.B. was an informant. The indictment says that MS-13 had "zero tolerance" for members or associates who cooperate with law enforcement and that once suspected, a "green light" could be issued authorizing that person be killed on sight.In June 2017, a man identified in the indictment as E.H. was killed with a machete and a knife.Authorities said non-gang members were also targeted, including a 34-year-old homeless man who was shot to death in January in a North Hollywood park claimed by the gang.Court documents said some of those charged posted photographs and messages to Facebook and other social media that appeared linked to the violence. Images showed the alleged gang members posing with weapons and in gang attire, and some of the pictures were taken close to the murder scenes and body dump sites.Multiple law enforcement sources told NBC News that investigators think the number of killings connected to the gang could be much higher than those detailed in the indictment.The charges in the indictment include allegations of a racketeering conspiracy against some defendants, murder and violent crimes in aid of racketeering.MS-13 was formed in Los Angeles in the 1980s by refugees who fled civil conflict in El Salvador, and it is organized in a loose structure of cells or "cliques," that control specific territory, according to a 2018 report by the Congressional Research Service.The gang became international as members were deported from the United States to Central America. Since 2005, law enforcement officials have estimated its membership in the U.S. around 10,000 members, contradicting suggestions that it has grown in the U.S. in recent years, the report said.MS-13 was named a transnational gang in 2012 during the administration of President Barack Obama. The Treasury Department announced it was targeting the organization with sanctions at that time.Named in the indictment are German Arnulfo Cruz Hernandez; Angel Amadeo Guzman; Ever Joel Morales; Fernando Garcia Parada; Jose Baquiax Alvarez; Kevin Villalta Gomez; Kevin Arteaga; Edgard Velasquez; Walter Chavez Larin; Yefri Alexander Revelo; Wilfredo Vides; Gerardo Alvarado; Roberto Carlos Mendez Cruz; Bryan Alberto Ordones; Roberto Alejandro Corado Ortiz; Edwin Isaac Mendez; Josue Balmore Flores Castro; Luis Arturo Gonzalez; Edwin Martinez; Steven Emmanuel Linares; Marco Antonio Ramos; and Erick Eduardo Rosales Arias.