Late at night on Long Island, when helicopters thrum overhead and spotlights beam down onto lawns, many people here know exactly what's going on.

'You just think, '"Oh, God, whose child is it now?"' said Stephanie Spezia, a longtime resident of Brentwood, New York, a suburb in the heart of Long Island that is caught in the grip of a violent street gang with Central American ties, MS-13.

With MS-13 blamed for a trail of 11 corpses of mostly young people found since the start of the school year in Brentwood and Central Islip, the nation's focus has turned on how the Central American street gang built such a presence here.

The bloodshed in the two blue-collar towns has gotten the attention of President Donald Trump, who says the killings are the result of lax immigration policies that let too many criminal 'scum' slip through.

Attorney General Jeff Sessions gave a speech Friday not far from a park where the bodies of four young men were found this month bearing MS-13's hallmarks: repeated slashes from a blade that left the victims nearly unrecognizable.

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Attorney General Jeff Sessions gave a speech Friday in Central Islip, not far from a park where the bodies of four young men were found brutally mutilated

A gang member of MS-13 is shown at a prison in Ciudad Barrios, El Salvador in this file photo. The Central American gang has established a strong presence in suburban Long Island

The casket of Justin Llivicura is carried from St. Joseph the Worker Church after Llivicura's funeral in East Patchogue, New York earlier this month. Llivicura, 16, was one of four young men found slain in a suspected MS-13 gang killing in a park on Long Island on April 12

The government's goal, he said, was 'to demolish' MS-13.

Until that happens, though, some parents say they are afraid to let their children go to school. Teens say any perceived slight to a gang member, especially a refusal to join, can mean death.

After one high school warned parents not to let their kids wear anything 'gang-affiliated,' gang members started deciding on a daily basis what colors were off-limits, leaving students to guess what not to wear.

'Kids are losing their childhoods,' said Jennifer Suarez, whose 15-year-old niece was beaten and hacked to death in the street last year. 'You can see the stress on their faces as they get ready. It's like, you know, they're suiting up for battle.'

So how does a street gang with ties to Central America gain such an aggressive foothold in the suburbs of Long Island?

MS-13, or the Mara Salvatrucha, is believed by federal prosecutors to have thousands of members across the U.S., primarily immigrants from Central America. It has a stronghold in Los Angeles, where it emerged in the 1980s as a neighborhood street gang.

But its true rise began after members were deported back to El Salvador in the 1990s. There, the gang thrived and spread to Honduras.

MS-13 and rival groups there now control entire towns, rape girls and young women, massacre students, bus drivers and merchants who refuse to pay extortion, and kill competitors or youths who simply refuse to join.

A family walks by a wall covered by a MS-13 symbol in El Salvador (file photo). Two suburbs on Long Island are in the grip of fear from the violent street gang with Central American ties

That violence has prompted a migration of people trying to escape, especially children, who have streamed north because of a U.S. policy allowing people under 18 who arrive without parents to stay in the country temporarily with relatives or friends.

Since the fall of 2013, the U.S. has placed 165,000 unaccompanied minors. Long Island has been a frequent landing spot. Suffolk County, which includes Brentwood and Central Islip, has gotten 4,500. Neighboring Nassau County has received 3,800.

In a recent roundup of 13 suspected MS-13 gang members accused of murder and other charges, seven had entered as unaccompanied minors.

'There's no question that MS-13 is recruiting these unaccompanied children,' said Suffolk County Police Commissioner Timothy Sini. The youngsters 'don't have an established social network, at least many of them don't, and MS-13 is providing that network.'

'They're also using coercion,' Sini said. 'They say, 'If you don't join the gang, we will kill you.''

Abraham Chaparro holds a photograph of his murdered stepson, Miguel Garcia-Moran, outside his home in Brentwood, New York on September 27. The remains of Garcia-Moran, who was reported missing in February, were found in September

All told, nearly 200 suspected MS-13 members have been rounded up since September. Among the tactics Sini has employed have been stepped-up patrols, renewed cooperation with an FBI task force and helicopter sweeps of wooded areas where gang members have been known to gather.

Trump has promised to eradicate the gang in the U.S. through strict enforcement of immigration law.

'We are putting MS-13 in jail and getting them the hell out of our country,' he told The Associated Press this week.

'They are a bad group, and somebody said they are as bad as al-Qaeda, which is a hell of a reference. ... We are out in Long Island cleaning out the MS-13 scum.'

The tough talk has made some residents fearful of law enforcement as well of the gang. They say it's not about immigration politics but about making a community safer.

Residents of Brentwood and Central Islip, with a combined population of about 100,000, say the area of modest ranch homes, warehouses and strip malls has always been a diverse, welcoming place for immigrants trying to make better lives for their children.

Some longtime residents say law enforcement bears some of the responsibility for the gang's rise because it ignored the burgeoning problem for years.

Emergency personnel walk near a crime scene where four bodies, believed to be the victims of the brutally violent MS-13 street gang were found in Central Islip, New York earlier this month

Parents say 4,200-student Brentwood High School lacks the means to help young people who are often left alone after school because their parents work long hours. There are few social workers and guidance counselors, they say, and not enough security guards or cameras.

'They can't walk the halls without fear,' said Evelyn Rodriguez, the mother of 16-year-old Kayla Cuevas, who was found beaten to death last fall. Rodriguez said her daughter had been bullied for two years.

In the months leading up to her death, Kayla was involved in a series of disputes with members and associates of the MS-13, prosecutors said. Rodriguez said her daughter stood her ground and ended up dead.

Kayla and her lifelong friend Nisa Mickens, 15, were walking on a street near their homes when men with baseball bats and a machete jumped out and attacked them.

Nisa was found dead on a residential tree-lined street a day before her 16th birthday. After a day of searching, Kayla was discovered in a wooded backyard nearby. She lived a block away.

'People, they missed the opportunity to know a really great person,' said Nisa's father, Rob Mickens, who is running for the school board to help push for change. 'They would have loved to know her.'

A poster featuring photos of Nisa Mickens and Kayla Cuevas is part of a memorial near the spot where their bodies were found in Brentwood in September. The best friends were murdered

A memorial to best friends Nisa Mickens and Kayla Cuevas is seen in this file photo. In the months leading up to her death, Kayla was involved in a series of disputes with members and associates of the MS-13, prosecutors said

Bertha Ullaguari said she noticed her 18-year-old son, Jorge Tigre, going from a good student on track to graduate from Bellport High to someone who was too afraid to go to school.

Then she got two truancy letters. When she pressed her son, he refused to tell her what was going on.

'Some bad things happened there,' Ullaguari said, her voice trembling. She had heard he had his tires slashed. There were rumors of gangs.

And then, about two weeks ago while she was driving with her daughter, they got a mysterious call. A girl on the line said Jorge was dead along with three others in a park 20 miles from his home.

'We nearly killed ourselves from the shock,' said Ullaguari, who is an Ecuadorean immigrant.

Jorge's body and the three others were found cut, their torsos exposed and hands bound, just steps from a playground.

'It could happen to anybody's child, anywhere,' Evelyn Rodriguez said. 'We all need to be aware of this, and we need stand together. Because I don't want it to be your child.'