The owner of a Minneapolis-based temporary work agency pleaded guilty in federal court in St. Paul this week to pocketing more than $425,000 withheld from employees' paychecks for taxes.

Doris Ruiz, a native of Peru, once served on Mayor R.T. Rybak's Latino Advisory Committee and started Olen Staff Co. in 2001. Federal agents shut down the company in 2008 during an investigation into allegations that she placed illegal immigrants with employers in Wisconsin and Minnesota and gave them false documentation.

In the plea agreement filed on Tuesday, Ruiz admitted that she collected and withheld about $150,292 from employees for federal income taxes and $276.897 for FICA taxes, which cover Social Security and Medicare. From 2005 to 2007, she did not pay taxes for herself or the workers.

She faces up to five years in prison for the charge. In exchange for the guilty plea and for agreeing to pay back all money owed, Ruiz escaped further prosecution and other charges relating to employment taxes.

Affidavits filed in federal court alleged that most of the workers Ruiz placed in factories, construction companies and other businesses were illegal immigrants.

In 2006, a Carlton County sheriff's deputy stopped Ruiz and three other adults in a car. Ruiz said they were on their way to a job site in Ashland, Wis. The U.S. Border Patrol later discovered the workers were in the country illegally. Two months later, a confidential informant posed as a job-seeker with no documentation and Ruiz set him up with a job and an apartment in Ashland.

Kaitlyn Walsh is a University of Minnesota student reporter on assignment for the Star Tribune.