Still, other hackers say the line between legal and illegal activity isn't murky at all, and as long as you've got a clean background, there's no reason to stop helping government agents catch criminals. Joel de la Garza, a security expert at Security, said he's been cooperating with the FBI for about five years. "I've never committed cybercrimes. I have nothing to fear," he said. "I want these people to come to justice." Martin Roesch, a well-known white hat who writes software which detects hacker activity, has also assisted in government investigations. He says his clean reputation means the Max Vision case won't impact any choice he might make to work with law enforcement. Like de la Garza, he attaches his real name to his computer security work, instead of using a pseudonym like most hackers -- but he concedes that has its drawbacks. "I've always been a white hat, tried to stay pretty squeaky clean," he said. "But being a white hat has its ups and downs. You aren't privy to a lot of information you might have if you had a fancy handle." And it's that inside information that federal agents can't resist, which is why some create their own online personas and attempt to gain the trust of noted computer criminals that way. Still, it's much easier to form uneasy alliances with known underground characters -- either by threatening them with arrest or purely paying them -- and take advantage of their existing relationships. "This is an important tool for law enforcement," said Tom Talleur, a federal investigator for 31 years, now a cybercrime consultant with KPMG. "Courts have held that it's legitimate... But it can have unintended consequences." For example, the informant may use information gleaned courtesy of the relationship to law enforcement to commit more crimes. That's a particular problem in any case that involves obsessive-compulsive informants like drug buyers, he said, who seem incapable of keeping promises to stay clean in the face of their overwhelming urges. Computer hackers are often obsessive-compulsive as well, he said, and will sometimes use information learned through their affiliation to break into government systems. Poulsen disagrees, pointing out that Butler's case is a rarity, that there are few examples of hackers for hire turning against the law enforcement group they're working for. When informants who are hackers engage in illegal behavior, he said, they rarely betray their "employer". Meanwhile, Butler's friends say they're sure he didn't take advantage of his relationship with the FBI, either. "Here's a guy who's done nothing but add to the state of security. If this case really does keep going forward, it's a sign of desperation on the part of law enforcement, grasping at a guy who has been helping," Ruiu said. Despite the complications of Butler's case, both hackers and federal investigators concede that for at least the near term, the FBI and other investigators will continue to turn to the computer underground for help -- both for technical expertise and access to individuals they can't find in the real world. "They are coming up to speed rather quickly from a technology standpoint," said Space Rogue, editor of the Hacker News Network Web site. "But you always need somebody on the inside who's familiar with the people." And despite the outcome of Max Butler's case, Poulsen thinks the flow of information between the groups won't slow down, because hackers will always want a chance to use their skills with impunity. "So it's a chance both sides have to take," he said. Go to Pt I/ Did FBI informant turn to the 'dark side'? Take me to the Summer of Hacking Special Take me to Hackers What do you think? Tell the Mailroom. And read what others have said.