(Portland, OR)  --  A convicted sex offender is facing two-and-a-half decades behind bars for sexual crimes against children.  A judge sentenced 36-year-old Andrew Heininge yesterday to 25 years in prison for the abuse of two children over a two-year period in Clackamas and Multnomah counties.  Heininge pleaded guilty to multiple charges, including three counts of first-degree rape and multiple sexual abuse charges.