(Portland, OR)  --  An inmate who escaped from the Columbia River Correctional Institute in Northeast Portland is back in custody.  Police say sex offender Matthew Medlin scaled a fence at the facility around 12:37 p.m. yesterday.  Medlin was found shortly before 10:00 last night at a Jack in the Box restaurant on Northeast Columbia Boulevard and Martin Luther King Boulevard.  Medlin's escape happened just six days before he was slated to be released.