This article is part one of a four-part series titled "The Gangs of Nantucket." Part two is available here. Part three is available here. Part four is available here.

Mara Salvatrucha, best known as MS-13, is a transnational gang based in El Salvador. It has about 10,000 members in the United States. In recent years, immigration officials have arrested and deported dozens of MS-13 and rival 18th Street gang members from Massachusetts to El Salvador. Some arrests were made in Revere, East Boston, Lawrence and in an unsuspecting location for gang activity in this state: Nantucket Island.

One day in May last year, we’re told that fog as thick as smoke had barely lifted over Nantucket Sound and the sun’s rays cut a slit through rainy grey clouds that landed on the deck of a ferry. Four agents attached to Immigration and Customs Enforcement, or ICE, were on board heading to the island. Matthew Etre, until recently the special agent in charge for Homeland Security Investigations in New England, a part of ICE, said, “We have to do like a lot of regular travelers and vacationers — take a ferry over to Nantucket.”

Fast speed ferry to Nantucket. “We have to do like a lot of regular travelers and vacationers: take a ferry over to Nantucket," says ICE's HSI New England director, Matthew Etre Phillip Martin/WGBH News

His agency’s order in May of 2016 was to apprehend reported members of two notorious street gangs with roots in Central America and tentacles that extend throughout the U.S. They are also present on this resort island, which many regard as the summer paradise of the rich. Houses here sell for upwards of $25 million, and foreign laborers are needed to do the jobs the rich can’t or won’t.

Resident Rodolfo Lemus runs down a list of jobs that are bringing immigrants here. “Driving taxis, working in restaurants, painting.” Lemus does manual work of all kinds here on Nantucket, and has carved out a decent life for him and his family. “I lived here for 17 years, and I like it because it is nice and quiet,” he said.

Rodolfo Lemus — now a U.S. citizen — arrived here from Agua Caliente, El Salvador. Today, it’s estimated that a little more than 3,000 Salvadorans have made their way to Nantucket, many escaping wide-spread gang violence in their home country.

Along with those seeking refuge have come small numbers of MS-13 cliques and its arch rival, 18th Street, also known as Barrio 18. Some of the island’s summer residents, like Hank Holliday — a wealthy South Carolina developer — are surprised to learn of a street gang presence on Nantucket, of all places.

“What? I'm shocked,” said Holiday. “They sort of stick out here. This is like La la land here. No gangs on Nantucket.”

We talked on the Nantucket pier where yachts bobbed up and down on green-blue water. Holiday has owned a house on Nantucket for 50 years and thought he knew the island well.

But many year-rounders, like a taxi driver who asked to remain anonymous, may know the island even better.

“I've heard of MS-13 on the island yes," the driver said. "It was in the newspaper. The incident where three gang members whacked the kid with a machete, and the kid did not testify against him in court. So, the judge had to throw it out.”

Isidro Lemus also recalled the incident. “There was a fight on Barlett Farm road,” he said. “And of course I know the kid. [He's] in the street all the time. I see him, walking back and forth. Him and his other gang members.”

Lemus, Rodolfo’s brother, also lives year-round on Nantucket. Just about everyone knows him by name and reputation. He has helped construct hundreds of homes — and painted hundreds more — in the 27 years he’s lived here. With his 11-year old son Eric by his side during this interview, Lemus said he fears running into the same gangs that members of his family moved to Nantucket to escape. “That's why every I'm trying to keep Eric away from the street," he said. "Either he goes with me or he doesn't go anywhere else.”

Why are these gangs here? As Central Americans have moved here over the past few decades, MS-13 and 18th Street have seized an opportunity to extort fellow immigrants — many undocumented and afraid to go to the police. Gang-related drug trafficking is also a growing concern.

“We recently sent a couple of police officers off to get some further training and being able to identify symbols on buildings, graffiti certain ways they conduct themselves," said Nantucket police Lt. Angus MacVicar, who heads up operations. "And we've been working with other outside agencies to sort of root out that issue before it grows and get some legs here in Nantucket.”

Isidro Lemus said he fears running into the same gangs that members of his family moved to Nantucket to escape. A captured gang member in El Salvador makes the Mara Salvatrucha's signs in a police station. Luis Romero/AP

Matthew Etre of ICE agreed. “As far as the operations on Nantucket, if there is a population that’s associated with gang activity, then we’re going to take action," he said. "Most recently you see this uptick in MS-13 gang violence and of course that’s where we’re going to focus resources.”

That’s why on May 11th last year ICE was here on Nantucket. Henry Lemus Calderon was one of those targeted. His cell rang that morning on his way to school. His uncle was on the line. “My uncle told me the immigration want you,” said Calderon.

ICE agents asked him to come down to the Nantucket police station. As Calderon told this story more than a year later in the custody of ICE, the chains around his ankles and wrists clanked.

“So, I went with my uncle to the police, and he don’t tell me nothing," Calderon said. "They put the handcuffs [on].”

That day ICE picked up five young men. Four had been involved in the machete incident that the taxi driver had read about in the newspaper. Two suspected members of MS-13 had left the island days earlier. One hid out in Rhode Island, the other in Utah, according to a confidential informant who spoke exclusively to WGBH News.

That afternoon, Calderon and the other four men were escorted by ICE agents onto a ferry to Hyannis. Zoila Gomez insisted that ICE and the Nantucket police erred in arresting Calderon as a gang member.

"If you look at my client, and if you look at his background and the particularities of his person and the record, it just doesn’t add up," she said.

Since the arrests in May 2016, some of the young men have been deported to El Salvador. Calderon is currently awaiting possible deportation.

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A Recent History Of Gangs On Nantucket

1980s and 1990s: Before a tiny clique of MS-13 and 18th Street gang members took root in Nantucket, a small group of Bloods ran drugs on the island in the late 1980’s and 1990’s, according to Nantucket police.

1998-2009: The FBI and Immigration officials in cooperation with Salvadoran police investigated a MS-13 leader with close connections to Nantucket. José Misael Cisneros Rodriguez, alias "Medio Millon" (Half a Million), led a clique in El Salvador. He is alleged to have murdered a witness there who knew about his criminal gang history on Nantucket, where he lived off and on from 1998 until 2009. He was arrested in Massachusetts for trafficking drugs on Nantucket and in other parts of the state. It’s unclear how he left the Bay State, but he was apprehended by Salvadoran police, put on trial and acquitted of murdering the witness in 2013, according to the Salvadoran newspaper, El Diario de Hoy. The investigative Latin American news-site InSight Crime also reported that in 2016 he was serving a prison sentence for extortion, gun-running and other crimes.

2007: In the first immigration sweep of its kind on the island on June 20, U.S. Immigration and Customs made 18 pre-dawn arrests. According to ICE, 16 of those arrested had prior criminal records, and several were connected to gangs. The Boston Globe reported, “Maryanne Worth, director of Nantucket's human services department, said the arrests reflect growing tensions within the immigrant community. She said gangs have begun forming on Nantucket, spawned by rivalries between immigrants from different Latin American countries.” ICE during this period also arrested alleged MS-13 members in Hyannis.

2015: On Jan. 17, 32-year-old Magno Sosa of Nantucket was murdered by 28-year-old Rigoberto Escobar, an 18th Street gang leader, while visiting friends in Everett. A police source said Escobar targeted Sosa because he was presumed to be a member of MS-13 on the island. But friends on Nantucket said it was a case of mistaken identity. Escobar was found guilty of first-degree murder, carrying a loaded firearm, possession of a firearm without a license and discharging a firearm within 500 feet of a dwelling. He was sentenced to life in prison without the possibility of parole. Although Sosa was known to associate with MS-13 members, there is no evidence to suggest he was a gang member.

2016: Henry Lemus Calderon, identified by a Nantucket High school resource officer as a member of the 18th Street gang, was detained by ICE agents along with four other young men on May 11. ICE was also seeking Carlos-Santos Benitez, a self-identified member of MS-13, who left Nantucket for Rhode Island weeks before the raid, according to sources who spoke with WGBH News.

2017: Over the summer, ICE returned to the island on at least one occasion to pick up an undetermined number of young men identified as gang members. In August, alleged MS-13 member Victor Lemus — no relation to Henry Lemus Calderon — returned to Nantucket from Utah, where he fled in 2016, weeks before ICE agents arrived to the island. In early September, following an immigration asylum hearing at the JFK Federal Building in downtown Boston, Lemus was arrested by ICE agents, who were waiting for him at the elevator outside immigration court. He was transferred to the Suffolk County Jail, but concerns about his safety prompted officials to transfer him to the ICE facility in Bristol County, where he is now awaiting possible deportation. Meanwhile, a former Nantucket High School Student, Erick Cangura, who was detained by ICE in 2016 on suspicion of belonging to MS-13, was deported to El Salvador earlier this year.

This story was edited by Aaron Schachter and Ken Cooper.