Los Angeles (CNN) It is 4:00 a.m., and a dozen ATF agents have poured out of an armored vehicle, preparing to break open the front and back doors of an inconspicuous store just outside downtown Los Angeles.

They suspect that storefront is a hub for the notorious MS-13 street gang

Rifle-wielding officers suited in body armor and helmets appear ready for combat. They go in, but there is no violence. With the element of surprise on their side, agents peacefully take a half dozen people into custody.

One by one, they come out in handcuffs. Some are suspected gang members; some may be victims of human trafficking, authorities say.

A storefront might seem like an odd place to find them. But MS-13 members have been known to live in storefronts and have been suspected of using them as a cover for drug activity, prostitution and human trafficking.

CNN's was the only TV crew that accompanied authorities during the raids.

At the same time, dozens of other raids were taking place across the city as hundreds of federal and local authorities stormed homes and storefronts, searching for high-ranking members of MS-13.

50 raids

The 50 pre-dawn raids, aimed at catching suspects asleep or off guard, also focused on nabbing members of MS-13's core leadership, the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) said.

"Today we disrupted this gang's command and control," said Eric Harden, special agent in charge of the ATF's Los Angeles field division.

Los Angeles is the US base for MS-13, which has tens of thousands of members worldwide. Authorities count the gang among the largest criminal organizations in the US.

Authorities carried out the largest crackdown of MS-13 members in Los Angeles history. They also found suspected human trafficking victims of the gang.

More than half of the 44 people arrested Wednesday are undocumented immigrants, acting US Attorney Sandra Brown said.

But the raids aimed to curb violent crime -- not immigration violations, Los Angeles Police Chief Charlie Beck said. He said MS-13 often "preys on" undocumented immigrants.

Authorities conduct one of 50 simultaneous raids targeting MS-13 gang members.

The suspects face a wide range of charges, including federal racketeering, narcotics conspiracy and homicide. If convicted, Brown said, most of those arrested Wednesday could face decades in federal prison -- and three could face the death penalty.

About 1,000 officers from the ATF, the FBI, the Drug Enforcement Administration, US Immigration and Customs Enforcement, the Los Angeles Police Department and the Los Angeles County Sheriff's Department took part worked on the massive effort.

And they had to execute their plan in the dark of night.

Investigation goes deep

Federal agents say the probe, which began in June 2014, targeted the leadership and the most violent members of MS-13 in Los Angeles and the gang's links to the Mexican mafia.

"We believe the most impact is made by targeting the mid- to upper-level hierarchy of the gang and removing them," Harden said.

"Once removed, it causes a disorganization of the gang, where it suppresses their activity for an extensive amount of time until another leader is developed or steps up."

MS-13 makes money from extortions, kidnappings, drug and weapons trafficking and human trafficking, the ATF said. Killings for the protection of the gang are common, federal authorities say, and sometimes are carried out with machetes.

Harden has faced off with MS-13 for decades, dating back to his days as a street agent.

"They've been here since the '80s and have thrived to this date," said Harden. "They're a transnational or international gang. Their level of brutality is extreme and high, similar to what we read about and hear with the drug-trafficking cartels in Mexico."

Gang has international reach

MS-13 began in Los Angeles in the 1980s, when El Salvadorians flooded into the United States. Its offshoot in Central America took hold when many of its members were deported.

The gang counts about 30,000 members worldwide and more than 10,000 in the United States -- a number that has held steady for some years but one that officials believe is trending upward, the Justice Department said.

MS-13 is active in 40 US states, plus the District of Columbia.

The gang is known for forcing new members to endure a 13-second beating known as "jumping in," authorities say. Members beat the new member with fists and bats in videotaped beatings often lasting far longer than the touted 13 seconds. Women who join the gang either jump in or are "sexed in," having sexual relations with MS-13 members.

Back in the spotlight

Despite Los Angeles authorities' long history fighting MS-13, the gang has found a recent spotlight under the Trump administration as part of its border security and immigration enforcement efforts. The administration, however, has failed to provide reporters with data on how many MS-13 members are believed to be in the United States illegally.

JUST WATCHED Trump's strong words for MS-13 Replay More Videos ... MUST WATCH Trump's strong words for MS-13 00:46

Just this week, at the National Peace Officers' Memorial Service, President Donald Trump said, "MS-13 is going to be gone from our streets very soon, believe me."

Last month, Trump tweeted that MS-13 was allowed to thrive under the immigration policies of the Obama administration, even though the gang has been in the United States for decades. Federal agents said the investigation that prompted Wednesday's raids began three years ago, under President Barack Obama and then-FBI Director James Comey.

There is little statistical evidence that MS-13 has been more prevalent in recent years or more dangerous to the US than other gangs, experts say.

"This attitude that there's a brand-new threat and it's new and it's all immigration, there is not a piece of that narrative that is accurate," said Jorja Leap, an anthropologist and longtime gang researcher at UCLA.

Even so, MS-13's methods are particularly brutal, experts say, and in recent months, several gruesome killings have made news across the nation.