Katona, 56, was charged in January with siphoning money from an investment pool belonging to the rural Lake Huron county where he was treasurer - an elected post - from 1993 until his dismissal last year.
State police said he authorized wire transfers totaling $186,500 last summer to overseas accounts linked to the well-known Nigerian scam. They suspect he lost more than $1.2 million in county funds altogether - plus $72,500 of his own money, despite a warning from his bank that he might be getting swindled.
"I'm sure if you were to ask Mr. Katona how did this happen, he'd just shake his head and say, 'I don't know how I let it happen, but I did,"' White said in a telephone interview.
Variations of the scheme have been around for years. They begin with unsolicited letters - or, increasingly, e-mails - seeking help in transferring millions of dollars from Africa to overseas accounts.
The recipients are typically offered a generous share of the money if they pay what they are told are upfront costs such as taxes, fees and bribes. Those who play along can lose large sums before realizing they've been fleeced.
Katona entered his pleas during a routine hearing ahead of a trial that was to begin later this month.
The Michigan attorney general's office, which is prosecuting the case, offered no plea bargain. White said Katona pleaded guilty to all charges to avoid wasting the court's time and money "proving what is very apparent."
Matt Frendewey, spokesman for Attorney General Mike Cox, said Katona's decision was "a testament of the strength of the case the state had against him."
Sentencing was scheduled for June 12. A count of forgery is punishable by up to 14 years in prison, while the maximum is 10 years for embezzlement and five years for attempted embezzlement.
"If he gets a long enough sentence, I think the county can start healing," said Kevin Boyat, chairman of the Alcona board of commissioners. "There's still going to be people mad for a long time."
Katona pleaded guilty to two felonies in 1998 after falsifying documents for private accounting clients. Under his plea bargain, the charges were dismissed after he stayed out of trouble for a year.
Voters re-elected him in 2000 and 2004.
Boyat said he hoped Katona would provide a detailed accounting of where the money went. The attorney general's office will seek restitution, Frendewey said.
It won't be clear how the thefts will affect Alcona finances until the state treasurer's office finishes auditing the county's books, Boyat said.
"It doesn't look real good," he said, adding that spending cuts might be needed.
