On or near New Year’s Day, members of the MS-13 gang beat and stabbed a young Virginia man using rocks, tree limbs and machetes, then sank his body in the water with a rock, according to prosecutors in Alexandria federal court.

Christian Alexander Sosa Rivas, 21, was lured to the Potomac River in Dumfries with an offer from a girl he once dated to smoke marijuana, according to an FBI agent’s affidavit unsealed Tuesday after four suspects appeared in court on murder charges.

"Comes what may," one alleged participant texted another after Sosa Rivas's corpse was found along the side of the river two weeks later.

“Yes, dog, for cause of La Mara Salvatrucha,” the other replied.

Jose Martir Larios Espenal, 20, or “Cannabis”; Samuel Enrique Villalobos Sanchez, 18, or “Rasta”; Edgar Oswaldo Blanco Torres, 24, nicknamed “Wizard”; and Dimas Misael Canales Santos, 27, or “Arcangel,” are charged with murder in the aid of racketeering and potentially face death sentences. So does Keyri Sujey Portillo Gonzalez, 18, known as “Katty Colon,” who prosecutors say helped lure Sosa Rivas to the woods and brought Pine-Sol to clean blood off the men’s machetes.

MS-13 graffiti marks a highway bridge in Springfield, Va., where police found 15-year-old Damaris A. Reyes Rivas’s body in February. (Michael Miller/The Washington Post)

The slaying of Sosa Rivas, of Fairfax City, is one of two intertwined MS-13 killings that have put 18 young people behind bars and sparked fears of a resurgence of the violent street gang in the D.C. area.

According to the affidavit, the killing was "green lit" by gang leaders in El Salvador and several of the participants expected promotions in the MS-13 hierarchy for taking part.

Sosa Rivas was killed because leaders of other MS-13 cliques in the region were angered that he was passing himself off as a leader of the gang, according to court records. However, the affidavit records Blanco Torres as saying that Sosa Rivas was killed because he had killed someone else, was stealing and was hanging out with another gang. He also said Sosa Rivas was part of the rival 18th Street Gang.

The defendants were identified by another MS-13 leader from Montgomery County, Md., who was arrested in January on unrelated charges, according to the FBI agent.

According to court testimony, 15-year-old Damaris A. Reyes Rivas of Gaithersburg, who was stabbed to death Jan. 8 in the Springfield area, was killed in retaliation for Sosa Rivas’s slaying.

Venus Romero Iraheta, 17, the girlfriend of Sosa Rivas and an MS-13 member, blamed Damaris for his killing and helped organize a revenge plot, a detective testified during a hearing in Fairfax County in May. Iraheta is being tried as an adult in Fairfax County.

The detective testified that Damaris was lured to a Springfield park and interrogated about Sosa Rivas's killing on the day she died. Damaris was made to remove her shirt on a frigid day, in part so she could feel the pain that Sosa Rivas felt, the detective testified. Iraheta reportedly later told Damaris that she would "see her in hell" and stabbed her 13 times with a knife. Another member of MS-13 allegedly gouged Damaris's neck with a large tree branch.

Damaris’s final moments were videotaped by gang members, and the cellphone recordings were discovered as detectives investigated the killing of Sosa Rivas.

Damaris was one of the last people to see Sosa Rivas alive, according to a search warrant filed in Prince William County court. But the federal affidavit relies on an unnamed cooperator who admits to helping lure Sosa Rivas to the woods and then fleeing to her car when the attack began.

Portillo Gonzalez later told the unidentified woman that they “could not have done this without her,” according to the affidavit.

Damaris had disappeared from home in mid-December and became involved with MS-13, her mother has said. Her body was found in February.

Four of the five federal defendants charged in Sosa Rivas’s killing made their first appearances Tuesday and asked for court-appointed counsel, who declined to comment. Larios Espenal did not have his first appearance.

Four of the five are scheduled to appear again for preliminary and detention hearings on Thursday. They were initially charged in Prince William County court.