Earlier this week, a federal judge sentenced Carl Mark Force IV to more than six years in prison after Force admitted to stealing hundreds of thousands of dollars' worth of bitcoins. It didn't help that Force himself was part of an undercover effort by the Drug Enforcement Administration to bust the virtual drug marketplace, Silk Road. Somewhere along the way, Force had turned to the dark side.

To many who aren't familiar with Bitcoin, an electronic form of cash, stories like these can make the online currency seem like catnip for criminals. Sen. Joe Manchin (D-W. Va.) last year urged a ban on Bitcoin for precisely that reason, saying it helped people "transacting in illegal goods and services or speculative gambling."

But now, as part of a wider effort to change Bitcoin's image in the minds of regulators and lawmakers, advocates of the technology have begun working with a group whose background and expertise make them well-respected within the Beltway: Federal law enforcement.

The Justice Department, Secret Service and other agencies are beginning to understand how to use Bitcoin for forensics — tracking flows of digital money across borders and online wallets just as they do with government-backed dollars. And the companies that handle these online transactions want to help. So they've created a first-of-its-kind trade group, known as the Block Chain Alliance, to reach out to federal officials.

The organization is designed as a one-stop shop where authorities who need a hand navigating the complex world of Bitcoin transactions can get advice and a steer in the right direction. Jerry Brito is the executive director of the Coin Center, and he helped bring together the 20-odd Bitcoin companies trying to build a relationship with governments both here and abroad.

"Law enforcement is coming across your traditional kinds of crimes where Bitcoin is the medium of exchange being used," said Brito. Their goal? "Try to find the bad guys."

Brito has been approached before by police for assistance. Several weeks ago, he said, Spanish authorities came to him asking for help tracking a suspect wanted for child molestation who they thought was using Bitcoin.

"This is the kind of thing where I can't help them, but I put them in touch with a company that might be able to help them track down this person," said Brito.

That was a one-off encounter. But Bitcoin makes it possible for law enforcement agencies everywhere to wield the technology in powerful ways, and they're increasingly savvy about it. You see, every transaction with Bitcoin is a matter of public record — by design. Even though you can't see who is paying whom, every individual bitcoin can be tracked as it makes its way across the ecosystem from one owner to another.

Jason Weinstein, a Washington lawyer who previously worked in the Justice Department's criminal division, helped pull together the Block Chain Alliance as a way to turn Brito's interaction with the cops into a more systematic process. In so doing, he wants to teach law enforcement that Bitcoin isn't all bad. And he hopes they'll pass the message along to policymakers.

"What's good for public safety is also good for business, and the growth of the industry," he said.

Weinstein likens Bitcoin to the Internet itself, which is certainly used by criminals but also powers billions of people's e-mail, online shopping, research and education and entertainment. And Bitcoin is similar to the Web in another respect, he said. When the Internet first took off, lawbreakers were running amok on a platform law enforcement didn't understand. Eventually, police began reaching out to technologists to understand it and get up to speed.

Now, Weinstein and Brito don't want to have to wait for the police to come knocking; they say this is the Bitcoin industry's way of proactively sharing what they can with the authorities.

This raises natural questions about privacy: How forthcoming are Bitcoin-using companies going to be in sharing their customers' data?

"That's where a lot of the discussion is going to be," said Brito. "What you need to do is, on the ends where you have on-ramps and off-ramps — the exchanges that exchange dollars for bitcoins — you need those to identify the people [you're searching for]."

Because these exchanges have to interact with the rest of the global banking system, letting consumers deposit and withdraw real-world money on demand, the vast majority are subject to the same data retention and reporting rules as other financial institutions, Brito said. While some might try to escape that government oversight and evade judicial due process, that'll likely hinder their ability to tap into the world financial system.