Firms that contract for the city of Denver may soon have to use the federal government's E-Verify system to prove their employees are legally entitled to work in the United States.  7News  reports that a city council committee has voted to forward to the full council a requirement that all construction companies that win contracts with the city check the citizenship status of their workers. Councilwoman Jeanne Faatz (top left) and Councilman Chris Nevitt are behind the idea, which comes after they received complaints about workers on a concrete job and learned 12 of the 25 employees for the private firm lacked proper Social Security numbers, according to the Denver Business Journal . Councilmen Paul Lopez (right) and Doug Linkhart fret that the E-Verify system, which is already required of federal contractors, could contain inaccuracies and cost people their jobs. Before you roll your eyes, consider the case of Marco Guevara. On the hunt for undocumented immigrants, the feds erred---big time---in Carbondale, after U.S. Immigrations and Customs Enforcement agents raided Guevara's home, threatening to send him to Ecuador, writes 7News , in a separate article. When Guevara turned to call his parents for help, he says he was tackled and handcuffed. Just one problem: Guevara is a U.S. citizen with a valid U.S. passport.