Six members of the ruthless MS-13 gang were indicted for racketeering in connection with the murder of a teen in Lynn, with the feds saying bail should be denied because they pose a serious threat to the public.

“The nature and circumstances of the (charges) are troubling and horrific,” a federal criminal affidavit reads.

That includes killing 17-year-old Herson Rivas on Aug. 2 with a large knife like they were “chopping wood.”

One of the accused, according to the affidavit, stabbed the defenseless teen “with such force his knife became warped during the attack.”

The teen’s body was found in a wooded park in Lynn. He was murdered, the U.S. attorney’s office in Boston said, because the MS-13 gang members — many illegal immigrants — believed he was cooperating with law enforcement.

One of the six accused, Henri Salvador Gutierrez, 19, of Somerville, dodged deportation a month before the murder.

“Salvador succeeded in convincing an immigration court that he was not in a gang, was not violent, did not pose a threat to the public,” the feds said.

The chilling motion for detention for all six adds: “Four of the six defendants appear to have entered or remained in the United Status unlawfully. At least four of the six defendants have MS-13 tattoos indicating that they are MS-13 homeboys, suggesting that they committed a murder or other violent attack.

“At least two of the six defendants have felony records. At least two of the six defendants were previously in immigration custody but were released and went on to commit … murder,” prosecutors state.

One of the suspects was arrested yesterday and the rest are locked up on state charges or in immigration custody, and will appear in federal court soon.

“MS-13 is a ruthless, transnational gang operating in our backyard,” said U.S. Attorney in Boston Andrew E. Lelling. “This group routinely commits senseless acts of violence, including murder, to maintain control and instill fear.

He added: “Dismantling MS-13 in Massachusetts and elsewhere is a top priority of the Department of Justice. Federal, state, and local law enforcement agencies will continue working together to investigate and hold MS-13 members responsible for these heinous crimes.”

Boston police Commissioner William G. Gross has also said dismantling MS-13 is a top priority.

The indictment charges the following members of the Sykos Locos Salvatrucha clique:

ERICK LOPEZ FLORES, a/k/a “Mayimbu,” 29, of Lynn;

HENRI SALVADOR GUTIERREZ, a/k/a “Perverso,” 19, a Salvadoran national previously residing in Somerville;

ELISEO VAQUERANO CANAS, a/k/a “Peligroso,” 19, a Salvadoran national previously residing in Chelsea;

JONATHAN TERCERO YANES, a/k/a “Desalmado,” 21, a Salvadoran national previously residing in East Boston;

MARLOS REYES, a/k/a “Silencio,” 22, a Salvadoran national previously residing in Chelsea; and

DJAVIER DUGGINS, a/k/a “Haze,” 29, of Lynn.