The City of Casper is working with the Wyoming Department of Revenue to figure out how to pay back $1.7 million that was erroneously deposited in city coffers by a company in Sweetwater County earlier in the decade, Mayor Ray Pacheco said.

The city, which has severely trimmed its budget, won't have to pay it back in one lump sum, Pacheco said after the regular council meeting Tuesday.

"Fortunately, working with the Department of Revenue, they're going to work with us so it's not just one hit, that they would give us the opportunity to pay it back over a span of time," Pacheco said.

The sales tax revenue was paid from an unidentified vendor in Sweetwater County, probably from 2011 to 2015, but somehow was routed to a city account, according to a recent audit, he said.

Councilmember Dallas Laird said during the council meeting the math in the repayment could be complicated somewhat because Sweetwater County has a 6 percent sales tax, compared to Natrona County's 5 percent sales tax.

Not all the money goes back to Sweetwater County, Pacheco said, because the state has a base 4 percent sales tax collected in all counties -- counties can vote to add up to 2 percent -- so the Department of Revenue will recover its share, too.

In a few weeks, representatives from the Department of Revenue will visit with city officials to talk about the details of what happened and figure out how to make sure this doesn't happen again, he said.

Probably no civil or criminal legal action will occur as a result because this appears to be an honest and unusual mistake, Pacheco said.

This is markedly different from what happened in the Town of Mills starting in January 2015.

An audit led to a Wyoming Division of Criminal Investigation probe of financial irregularities in the town. Former town clerk/treasurer Lisa Whetstone later pleaded guilty to one felony count of using a public credit card for personal purposes and at her sentencing was ordered to pay $60,000 she embezzled from the town.

The audit also found the town advertised the sale of three properties in February 2014, and former Mayor Marrolyce Wilson acquired them through her daughter. Wilson resigned as mayor. In April 2017, she pleaded no contest to one misdemeanor count of official misconduct and was fined the legal maximum of $5,000.