(Portland, OR)  --  Authorities are looking for a fugitive involved in the shooting of a Portland police officer last year.  A nationwide warrant has been issued for 26-year-old Jemaell Diamond Riley, who officials say cut off his ankle monitoring bracelet.  Riley was one of three suspects arrested after the shooting of Officer Jeff Dorn and his K-9 last April.  Police believe he's accompanied by 20-year-old Carli Marshall.