(Hillsboro, OR)  --  A registered sex offender from Colville, Washington is facing charges after allegedly driving to Oregon to meet a child for sex.  The Washington County Sheriff's office says that 48-year-old Allen Williams chatted online with a child he believed was a 15-year-old girl for nearly two years.  Instead, it was an undercover detective from the Violent Crimes Unit.  Police arrested him in Washington County on charges of Online Sexual Corruption of a Child and Luring a Minor.  Williams has been a registered sex offender since 2002.