A Colorado cleaning company is suing its competitors, claiming they hired illegal immigrants and were able to low-ball bids.For 15 years, Steve Blacker's janitorial company Dustbusters cleaned Boulder's public library.A few years ago, though, Longmont-based The Finishing Touch agreed to do it for $20,000 less."It's unfair competition," said Stan Weekes with the Colorado Alliance for Immigration Reform.He said Dustbusters' owner did some digging."It would appear that he gained street evidence from people who know, that talked to people, that they were hiring illegals," said Weekes.The lawsuit alleges that Finishing Touch knowingly employed "illegal aliens," could pay them less and could underbid competitors.The owner of The Finishing Touch would not comment, but her attorney said the charges are false."I am confident that the end result will be in my client's favor," said Bart Dunn, an attorney for The Finishing Touch.Steve Hendrickson owns a cleaning company that was initially named in the suit, but said the allegations were dropped because he was able to prove his workers were legal."It is a problem in the cleaning industry," he said. " But we're a company that really does believe you should follow the law."Immigration reform advocates say the law is not being enforced in criminal courts, so the only recourse for business owners may be in civil trial.Whether Dustbusters wins the $400,000 they're asking for or not, Weekes said the case sends an unprecedented message to business owners."They are possibly going to be held responsible for hiring illegals," said Weekes.The trial started Monday and is expected to take three days. The plaintiff waived the right to a jury, so a judge will make the ruling.