Despite endless denials from Democrats that a suburb of Colorado’s largest city was an operating base for a Venezuelan gang, federal officials this week indicted 30 suspected leaders and members of the Tren de Aragua syndicate, charging them with drug and weapons trafficking and a “barbaric” murder-for-hire plot.

Federal prosecutors say the investigation began in October 2024 when the Arapahoe County sheriff’s office noticed a spike in violent crime at the Ivy Crossing apartment complex at Aurora, a suburb of Denver — a scene captured in a video that went viral on social media.

“The charges tell a story of people selling guns and drugs. Lots of them,” U.S. Attorney Peter McNeilly said during a press conference. “The affidavits which have been filed in this case also tell a story of a murder-for-hire plot and other crimes that the defendants were willing to commit, such as sex trafficking.”

“One of the people who offered to commit murders in this case bragged to the undercover officers that the people he would use to commit those murders were the very same people that we had seen committing crimes on the news in these apartment complexes in Aurora,” Mr. McNeilly said.

“TdA has brought its terrorism to the United States. TdA is real, it is dangerous, and we have made prosecuting TdA a priority in the District of Colorado,” he added.

When the viral video — which showed heavily armed men who were allegedly TdA members kicking down an apartment door at Aurora — made headlines in 2023, Democrats came out of the woodwork to declare that the city was not a gang stronghold. 

“There is no gang takeover in any part of Aurora,” a state representative, Jason Crow, posted on X. The governor of Colorado, Jared Polis, said through a spokesman that the “purported invasion” is largely a figment of one Republican lawmaker’s “imagination,” condemning what he called “recent misinformation campaigns.”

Even Vice President Kamala Harris denied that there was gang activity in Colorado during the September 10, 2024, presidential debate. President Trump mentioned Aurora twice in the debate, claiming that criminal immigrants were “taking over the towns, they are taking over buildings, they are going in violently.” He vowed to “liberate Aurora” after reports emerged that TdA gang members were extorting apartment building residents for protection payments.

The 10-month federal investigation, described by officials as “the biggest investigation” of the TdA gang in the United States, led to the indictment of two suspects considered among those “most responsible” for the alleged crimes — Luis Fernando Uribe-Torrealba and Luis Henriquez Charaima, both 29. The pair were arrested by Colombian authorities at Medellín on July 30 following provisional arrest warrants being issued by the United States. 

Five defendants face conspiracy charges in connection with a murder-for-hire scheme in which suspects allegedly agreed to kill two people for $15,000, with an additional $5,000 offered for delivering the victims’ severed heads as proof. Of the 30 people charged, 24 are currently in federal custody. Two await extradition from Colombia.

Working with the Bureau of Alcohol, Tobacco, Firearms and Explosives, investigators launched some 40 undercover operations targeting gun sales and trafficking of tusi, a synthetic drug mixture also known as “pink cocaine.”

The investigation yielded significant seizures, including 69 firearms — some equipped with machine gun conversion devices — and “pounds” of narcotics. Several weapons have been linked to shootings, carjackings, robberies, and drive-by shootings at Denver and Aurora, according to authorities.

The Arapahoe County sheriff, Tyler Brown, reported significant improvements in the targeted area since the operation began.

“Each one of those 69 guns represents the saving of a life. Each ounce of narcotics taken off the street represents a life saved,” Mr. Brown said. “This community has seen a 75 percent reduction in calls for service. … That is life-changing for the people in this community.”

Denver and Aurora, a city of 400,000 people, are both “sanctuary cities,” meaning illegal immigrants can live there without fear of persecution.

Thousands of Venezuelans who poured across the border during President Biden’s term were bused north by the governor of Texas, Greg Abbott, with hundreds arriving at Denver each day. The city converted seven hotels into shelters and provided housing assistance and other services, but thousands more were moved to Aurora.

Mr. Trump has targeted TdA directly. In March, he invoked a 1798 wartime law, the Alien Enemies Act, which allows a president to deport foreigners if they are citizens of countries judged to be “enemies” of the United States. Mr. Trump declared that TdA was coordinating with the Venezuelan government to undermine American national security.