A worker at a drug testing center admitted she accepted payments of cash or pot to conceal evidence of inmates' and suspects' failed drug tests.

Amanda Winter, 22, of Lansing pleaded guilty Wednesday in Grand Rapids federal court to public corruption. Winter worked at Insight Recovery Center, a federal contractor.

She admitted taking the payments from convicts and federal defendants to ignore positive preliminary urine tests.

The charge carries up to 15 years' imprisonment and a $250,000 fine. Under the plea deal, she agreed to cooperate with investigators and the sentencing judge will be informed of her cooperation.

The Oct. 15 indictment said that between June 2007 and June 2008, Winter took payments from people whose urine samples came up positive on preliminary drug tests in exchange for not reporting the tests. Because she did not report the positive tests, the samples were discarded rather than tested further.

Winter also warned some people that they were scheduled to be tested, the indictment said.

The chief executive of Insight Recovery Center, Tom Dreyer, did not immediately return a call seeking comment. Defense lawyer Britt Cobb also did not return a call.