HARTFORD, Conn. (AP) -- A man says he was tortured for weeks in a New York townhouse. Another in Paris was held for ransom and his finger cut off. A couple in Connecticut were carjacked, beaten and thrown into a van.

All, authorities allege, were victims tied to cryptocurrency-related crimes that have spilled out from behind computer screens and into the real world as the largely unregulated currency surges in value.

While crypto thefts are not new, the use of physical violence is a far more recent trend, said John Griffin, a finance professor at the University of Texas in Austin who tracks financial crimes.

"I think this kind of physical violence is a natural manifestation of the emboldened nature of crypto activities," he said. "Things that might clearly be outside of social norms in other spaces -- like robbing a bank -- are somehow just part of the game here."

In the New York case, two American crypto investors -- John Woeltz and William Duplessie -- have been arrested on kidnapping and assault charges in recent days after a 28-year-old Italian man told police they tortured him for weeks to get his Bitcoin password. Attorneys for both men declined to comment.

While the allegations are still emerging, they come just weeks after 13 people were indicted on federal charges in Washington, D.C., accused of combining computer hacking and money laundering with old-fashioned impersonation and burglary to steal more than $260 million from victims' cryptocurrency accounts.

Some are accused of hacking websites and servers to steal cryptocurrency databases and identify targets, but others are alleged to have broken into victims' homes to steal their "hardware wallets" -- devices that provide access to their crypto accounts.

The case stemmed from an investigation that started after a couple in Connecticut last year were forced out of a Lamborghini SUV, assaulted and bound in the back of a van. Authorities allege the incident was a ransom plot targeting the couple's son -- who they say helped steal more than $240 million worth of Bitcoin from a single victim. The son has not been charged, but is being detained on an unspecified "federal misdemeanor offense" charge, according to online jail records. Police stopped the carjacking and arrested six men.

Meanwhile in France, kidnappings of wealthy cryptocurrency holders and their relatives in ransom plots have spooked the industry.

Attackers recently kidnapped the father of a crypto entrepreneur while he was out walking his dog, and sent videos to the son including one showing the dad's finger being severed as they demanded millions of euros in ransom, prosecutors allege. Police freed the father and arrested several suspects.

Earlier this year, men in masks attempted to drag the daughter of Pierre Noizat, the CEO and a founder of the Bitcoin exchange platform Paymium, into a van, but were thwarted by a shopkeeper armed with a fire extinguisher.

And in January, the co-founder of French crypto-wallet firm Ledger, David Balland, and his wife were also kidnapped for ransom from their home in the region of Cher of central France. They also were rescued by police and 10 people were arrested.

The FBI recently released its 2024 internet crime report that tallied nearly 860,000 complaints of suspected internet crime and a record $16.6 billion in reported losses -- a 33% increase in losses compared with 2023.

As a group, cryptocurrency theft victims reported the most losses -- more than $6.5 billion

The agency and experts say the crypto crime underworld is likely being fueled by the large amounts of money at stake - combined with weak regulation of cryptocurrency that allows many transactions to be made without identity documents.

Violence may be increasing for several reasons including that criminals believe they can get away with crypto theft because transactions are hard to trace and often cloaked by anonymity, according to the crypto tracing firm TRM Labs. And crypto holders are getting easier to identify because of the prevalence of personal information online and people flaunting their crypto wealth on social media, the firm says.

Phil Ariss, TRM Labs' director of UK public sector relations, said crypto also may be attracting criminal groups that have long used violence.

"As long as there's a viable route to launder or liquidate stolen assets, it makes little difference to the offender whether the target is a high-value watch or a crypto wallet," Ariss said in a statement. "Cryptocurrency is now firmly in the mainstream, and as a result, our traditional understanding of physical threat and robbery needs to evolve accordingly."