The U.S. government has long warned that Russian organized crime posed a threat to democratic institutions, including "criminally linked oligarchs" who might collude with the Russian government to undermine business competition.

Those concerns, ever-present if not necessarily top priorities, are front and center once more.

An ongoing special counsel investigation is drawing attention to Russian efforts to meddle in democratic processes, the type of skullduggery that in the past has relied on hired hackers and outside criminals. It's not clear how much the probe by former FBI Director Robert Mueller will center on the criminal underbelly of Moscow, but he's already picked some lawyers with experience fighting organized crime. And as the team looks for any financial entanglements of Trump associates and relationships with Russian officials, its focus could land again on the intertwining of Russia's criminal operatives and its intelligence services.

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Russian organized crime has manifested itself over the decades in more conventional forms of money laundering, credit card fraud and black market sales. Justice Department prosecutors have repeatedly racked up convictions for those offenses.

In recent years, though, the bond between Russian intelligence agencies and criminal networks has been especially alarming to American law enforcement officials, blending motives of espionage with more old-fashioned greed. In March, for instance, two hired hackers were charged along with two officers of Russia's Federal Security Service in a cyberattack on Yahoo Inc. in 2013.

It's too early to know how Russian criminal networks might fit into the election meddling investigation, but central to the probe are devastating breaches of Democratic email accounts, including those of the Democratic National Committee and Hillary Clinton's campaign chairman. U.S. authorities have blamed those hacks on Russian intelligence services working to discredit Clinton and help Trump — but have said the overall effort involved third-party intermediaries and paid Internet trolls.

Former law enforcement officials say Russian organized crime has been a concern for at least a couple of decades, though not necessarily the most pressing demand given finite resources and budget constraints. The threat is diffuse and complex, and Russia's historic lack of cooperation has complicated efforts to apprehend suspects. And the responsibility for combatting the problem often falls across different divisions of the FBI and the Justice Department, depending on whether it's a criminal or national security offense — a sometimes-blurry boundary.

"It's not an easy thing to kind of grasp or understand, but it's very dangerous to our country because they have so many different aspects, unlike a traditional cartel," said Robert Anderson, a retired FBI executive assistant director who worked counterintelligence cases and oversaw the criminal and cyber branch.

"You have to know where to look, which makes it more complicated," he added. "And you have to understand what you're looking for."

Federal prosecutors continue to bring traditional organized crime cases, such as one last month in New York charging 33 members and associates of a Russian crime syndicate in a racketeering and extortion scheme that officials say involved cargo shipment thefts and efforts to defraud casinos. But there's a heightened awareness about more sophisticated cyber threats that commingle the interests of the government and of criminals.

"An organized criminal group matures in what they do," said retired FBI assistant director Ron Hosko. "What they once did here through extortion, some of these groups are now doing through cyberattack vectors."

Within the Justice Department, it's been apparent since the collapse of the Soviet Union that crime from that territory could affect national security in Europe and the U.S.

A 2001 report from the Justice Department's National Institute of Justice, a research arm, called America "the land of opportunity for unloading criminal goods and laundering dirty money." Three months later came the Sept. 11 attacks, and the FBI, then under Mueller's leadership, shifted resources to focus on terrorism.

"I recall talking to the racketeering guys after that and them saying, 'Forget any focus now on organized crime,'" said James Finckenauer, an author of the report.

Besides cyber threats, Justice Department officials in recent years have worried about the effect of unchecked international corruption, creating a kleptocracy initiative to recover money plundered by government leaders for their own purposes.

In 2014, then-Attorney General Eric Holder pledged the Justice Department's commitment to recouping huge sums believed to have been stolen by the ousted Russian-backed government of Viktor Yanukovych, the Ukrainian president chased from power earlier that year. That effort led to an FBI focus on Paul Manafort, the Trump campaign chairman who lobbied for Yanukovych's government and who remains under investigation now.

But those same foreign links have also made cases hard to prove in court. In many instances, foreign criminal hackers or those sponsored by foreign governments — including China, Iran and Russia — have remained out of reach of American authorities. In some cases, judges have chastised U.S. authorities for prosecutorial overreach in going after international targets.

A San Francisco federal judge, for instance, in 2015 dismissed an indictment involving two Ukrainian nationals who'd been accused of trying to bribe an official at a United Nations agency responsible for creating standards for machine-readable international passports.

The judge said he couldn't understand how the government could apply a foreign bribery law to conduct that had no direct connection to the U.S.