Corey Davis was a good role model. At least that's what the state Department of Human Services thought when it paid him and his company, We Mentor Inc., nearly $700,000 to counsel some 300 troubled boys and girls between 2001 and 2004. In reality, the budding entrepreneur had a felony drug conviction and owed thousands of dollars in child support to two women. Some of the people he employed also had criminal backgrounds. But the state blindly nurtured Davis until learning one of his mentors had cracked up a car last summer, injuring a 6-year-old boy. The resulting collapse of...