Prosecutors in Los Angeles have accused members and associates of the MS-13 gang of seven murders, including several in which victims were hacked to death with machetes in a southern California forest.

The indictment by the US attorney’s office in Los Angeles unsealed on Tuesday charges 22 people linked to the Fulton clique, a subset of the MS-13 street gang. They are suspected of nearly 200 crimes in several states over nine years, the indictment said.

MS-13, or La Mara Salvatrucha, was formed in Los Angeles in the 1980s by refugees from El Salvador and is linked to killings across the US. Donald Trump has singled out the gang as a threat to the US and blames weak border enforcement for the group’s crimes. Many MS-13 gang members, however, were born in the US.

The indictment alleges that on 6 March 2017, several MS-13 members abducted, choked and drove a member of a rival gang who they believed had defaced MS-13 graffiti to a remote area of the Angeles national forest.

At the forest, six people dismembered the rival gang member with a machete and threw the body parts into a canyon, after one cut the heart out of the body, the indictment says.

Six killings were committed by gang members hoping to gain entry into or advance within the clique’s ranks, according to the indictment.

Officials called the killings so “heinous, cruel or depraved” that the defendants are eligible for the death penalty. Prosecutors have not said whether they intend to seek capital punishment.

All 22 of the alleged MS-13 members and associates are in custody. Eighteen had been apprehended over the last year on a range of federal and state charges, authorities said. Three were arrested in recent days in the Los Angeles area by a taskforce that included FBI agents, Los Angeles police officers and Los Angeles county sheriff’s deputies. Another alleged MS-13 affiliate was arrested over the weekend in Oklahoma.

Authorities also filed two more cases under seal against juvenile defendants in federal court.