A federal indictment unsealed in court Tuesday expresses investigators’ belief the skeletal remains found in the Tick Fire burn area are connected to a series of 2019 murders attributed to international street gang MS-13.

After four additional suspects were arrested this week, the 18-count indictment was unsealed, alleging 31 “members and associates of MS-13 murdered 11 people, five of whom were hacked to death with machetes or knives in the Angeles National Forest.”

The latest indictment expands on one previously filed Aug. 5 and includes the alleged Santa Clarita murder.

Detectives from the Los Angeles County Sheriff’s homicide department collect a set of human remains reported in a burned area alongside Sand Canyon Road for investigation. October 26, 2019. Bobby Block / The Signal.

According to the court document, defendant Walter Chavez Larin — who is known by a number of aliases but is listed in the complaint as “Chavez” — is a known “shot caller” and “leader” of  MS-13’s Fulton clique.

“On Jan. 13, 2019, defendant Chavez ordered O.F.’s (the victim) murder because O.F. abandoned MS-13 and was addicted to methamphetamine,” the indictment reads.

Later that same day, Chavez handed one of his co-conspirators a .38-revolver and ordered that O.F. be shot. After exchanging coded messages on Facebook messenger, defendants Chavez, Yefri Alexander “Silent” Revelo, Edwin “Desorden” Martinez and Carlos Daniel “Chellito” Orellana Gonzalez took O.F. from Whitsett Park out to a remote part of Santa Clarita.

The complaint states Gonzalez and Martinez discussed, via Facebook messenger, they wanted the opportunity to kill O.F. “so that they could become homeboys with MS-13.”

“On January 13, 2019, in Santa Clarita, defendant Martinez punched O.F. in the face, a co-conspirator shot O.F. with a .38 revolver and passed the gun to defendant Martinez, who shot O.F. and passed the gun to defendant Orellana, who shot O.F., while defendants Chavez and Revelo waited in a vehicle,” the complaint reads. “On January 13, 2019, defendant Chavez confirmed that the co-conspirator shot O.F.”

Detectives from the Los Angeles County Sheriff’s homicide department collect a set of human remains reported in a burned area alongside Sand Canyon Road for investigation. October 26, 2019. Bobby Block / The Signal.

After killing O.F., whose name was not disclosed in the complaint, the defendants then went to a home in Reseda and buried the shell casings. Within a few hours Martinez and Gonzalez would be headed out to successfully commit another murder in Whitsett Park, according to the complaint.

Mara Salvatrucha — which would eventually become associated with the Mexican Mafia, or MS-13 — took root in Los Angeles in the 1980s, according to a news release about the indictment. The 13 was reportedly added due to “M” being the 13th letter of the alphabet and to become a new member of a Mexican Mafia-affiliated gang, an individual had to subject themselves to a 13-second beating from the other members of the gang.

The MS-13 Fulton clique, according to the release, where the defendants stemmed from, operates out of the San Fernando Valley and alleges that in addition to O.F.s murder, the 31 defendants listed in the complaint are connected to 10 other murders.

“The RICO charge alleges nearly 300 ‘overt acts,’” including acts involving murder, drug trafficking and extortion,” the news release reads.

The new indictment was unsealed just before scheduled arraignments for three new defendants who were taken into custody in the Los Angeles area, according to the complaint. The fourth new defendant was arrested in Colorado. Two new defendants were already in federal custody, and three new defendants were already in state custody.

The RICO case was the product of Los Angeles County Sheriff’s Department officials, the Los Angeles Police Department and the FBI working together to solve the mysterious case of the skeleton found in the burn area of the Tick Fire.

The skeleton, found on Oct. 26, 2019, was discovered by a public works employee who had come across it while surveying the area scarred by the Tick Fire, which broke out a few days earlier.

Investigators said at the time that the bodily remains were in an “odd place for … somebody to just walk up there and die.”

On Wednesday, Sarah Ardalani, a spokeswoman for the Los Angeles County Medical Examiner-Coroner’s Office said that the body remained “Undetermined Doe No. 20.”

“The investigation into this death is ongoing and I’m unable to provide the report at this time,” said Ardalani.