"Doc" slipped in and out of Warroad, buying drugs and guns while living outside the law himself.
DULUTH - Craig Allen Hartline is a convicted sex offender, but when he moved to Minnesota last year he didn't register, which is a felony. He earned $14,000 while working here, but didn't file a tax return and admits he hasn't filed one since 1983.
He also drove his van back and forth across the state, without a license.
How did Hartline go unnoticed by state law enforcement authorities?
They were paying him.
Officials said Friday they were surprised and somewhat embarrassed to learn they planted an unregistered sex offender in Warroad last year when they hired the 55-year-old Hartline, called him "Doc" and set him up to buy drugs and guns in the back of a secondhand store.
Agents fitted "Doc's Superthrift Store" in the town's old Hardware Hank building with hidden microphones and cameras. The purchases he made there for the Minnesota Bureau of Criminal Apprehension (BCA) and local police led to charges against 53 people, 30 of whom have pleaded guilty so far.
Police and prosecutors were happy with Doc's work, but admit being distressed to learn in preparation for trials that he had been convicted of a sex offense in Massachusetts in 1993, was registered in that state as a sex offender and hadn't registered in Minnesota as required when the BCA invited him to work here.
He told agency officials he had pleaded no contest to a trumped-up charge and didn't think it was something he had to disclose, and it hadn't turned up during an earlier background check.
"We hit some bumps in the road with this operation," Roseau County Attorney Lisa Hanson acknowledged. "But for the most part it went smoothly, and the results were good."
While attorneys who represent some of the defendants acknowledge that sometimes it takes a crook to catch a crook, they say it's unfair for Doc to get off for his crimes while their clients battle charges they wouldn't face if he hadn't offered them the opportunity.
"The BCA has an entire program to compel [sex-offender] registration, and then they give this guy a pass and let him handle weapons and not pay taxes," said Fred Friedman of Duluth, chief public defender for northeastern Minnesota. "Someone ought to be ashamed of themselves."
'We don't turn a blind eye'
Whether things would have been done differently if officials had known about Doc's background is uncertain.
"Had we known his whole background, it would have been factored in to our decision on whether to use him," said Dave Bjerga, the BCA's assistant superintendent. "But I don't know what the decision would have been."
A representative for the federal Bureau of Alcohol, Tobacco and Firearms (ATF), which had used Hartline in a similar operation in North Dakota just before the Warroad sting, said she wouldn't be able to comment on whether he's still working for ATF.
"It would be nice if we were able to say all our informants have clean backgrounds, but unfortunately that's probably never going to be the case," said Sherry Duval, public information officer for the ATF's office in St. Paul. "But we don't turn a blind eye. If we know they're committing criminal activity while we're using them, they're done."
A year ago, Doc suddenly left Warroad, a Canadian border town of 1,700, after only four months there and 63 law-enforcement officers suddenly swarmed in to make arrests. Local folks said it didn't surprise them to learn that Doc was a snitch.
"He left just as suddenly as he came," Jackie Bengtson, owner of the Main Street Bar & Grill, said at the time. "We didn't feel creeped out by him, but he was a shady character."
Poll: Which free-agent quarterback would you most like the Vikings to sign?