BRENTWOOD, N.Y. (CBSNewYork) — Members of the MS-13 gang have been arrested in connection to the murder of two teenage girls and a third teenager in Brentwood.

Four MS-13 members, including four members identified by authorities as A. Saenz, J. Saenz, Selvin Chavez and Enrique Portillo were charged Thursday in connection with the murders of 15-year-old Nisa Mickens and 16-year-old Kayla Cuevas, who were found dead in Brentwood in Sept. 2016.

More: Read The Full Indictment

Elmer Alexander Lopez, German Cruz, and two other suspects who authorities say are still at large, were also charged in connection with the murder of Jose Pena-Hernandez, a known MS-13 gang member whose remains were found in a wooded area near the Pilgrim Psychiatric Center in October 2016.

A broader 41-count indictment against 13 members of MS-13 includes charges connected to seven murders, attempted murders, assaults, racketeering, obstruction of justice, arson, conspiracy to distribute marijuana, and related firearms and conspiracy charges, according to the U.S. Department of Justice.

“Ten of those defendants are illegal aliens, two are U.S. citizens and one is a green card holder,” U.S. District Attorney Robert L. Capers said.

If convicted on federal murder charges, the defendants face life in prison without the possibility of parole, or the death penalty, Capers said.

“I want to say thank you so much from the bottom of my heart. This day is a celebration, but also today is, it’s a sad day because Kayla is not here,” her mother Evelyn Rodriguez said.

On Sept. 13, the day before her 16th birthday, Nisa Mickens’ brutally beaten body was found on a tree-lined street. The next day, the beaten body of her lifelong friend, 16-year-old Kayla Cuevas, was discovered in the wooded backyard of a nearby home.

As CBS2’s Carolyn Gusoff reported, authorities say Cuevas was “marked for death” after she had feuded with MS-13 members at Brentwood High School and on social media. Mickens, who was with Cuevas on the night of her death, was just at the “wrong place at the wrong time,” Capers said.

“She was simply hanging out with her childhood friend,” Capers said.

According to the indictment, Chavez, A. Saenz, J. Saenz, Portillo and other members of the Sailors Locos Salvatruchas Westside MS-13 clique were out looking for rival gang members to kill when they recognized Cuevas walking along Stahley Street. According to authorities, A. Saenz and J. Saenz, the leaders of the clique, authorized killing Cuevas and Mickens before Portillo and several other gang members attacked the teens with machetes and baseball bats.

Pena-Hernandez was targeted because fellow MS-13 members suspected he may have been cooperating with police, and had possibly violated other rules within the MS-13 code, authorities said.

“For them, all those transgressions were punishable by death,” Capers said.

According to the indictment, members of the gang lured Pena-Hernandez into a car on Jun. 3, 2016, and drove out to a wooded area by the Pilgrim Psychiatric Center that they typically used as a hangout.

“At that moment, Pena thought he was surrounded by friends,” Capers said. “But these friends turned on him and attacked him.”

When they arrived at the scene, authorities say Cruz and Lopez took turns slashing Pena with knives.

According to Capers, all three teens who were killed attended Brentwood High School.

The killings, a few of many, sparked outrage and fear throughout the community.

“For far too long on Long Island, MS-13 has been meting out its own version of the death penalty against members of their gang who violate their so-called ‘rules,’ against rival gang members they seek to eliminate over disputes, and anyone else they decide they want to seek revenge against for any reason they so choose,” Capers said.

In September 2016, police also discovered the skeletal remains of 19-year-old Oscar Acosta and 15-year-old Miguel Garcia-Moran in a remote industrial area of the town. Acosta had been missing since May, and Garcia-Moran vanished in February.

The body of a 34-year-old Brentwood man, identified as Dewann Stacks, was also found dead on a Brentwood street in October. He was apparently beaten in the head.

The Suffolk County Police worked with the FBI with the intention to help dismantle an increasingly violent street gang.

Sini said the Suffolk County Police Department will continue to gather intelligence and work to crack down on gang-related crime.

“We have promised to eradicate MS-13 from our streets, and we remain fully committed to this job,” Suffolk County Police Department Commissioner Tim Sini said. “…We will not let up until the job is done.”

Five gang members arrested on Thursday in connection with the indictment will be arraigned in court Thursday afternoon.