(Portland, OR) -- A bias crime investigation is underway into potentially racist graffiti in North Portland. The Portland Police Bureau says someone wrote the words "whites only" on the door of an apartment unit. The resident who lives in the unit tells police the suspect knocked on the door and then forcefully tried to open it before leaving and returning ten minutes later with a blow torch. The resident called 9-1-1, and responding officers found the graffiti. Police are still searching for the suspect.