(Portland, OR)  --  Police are investigating a report that a man with a gun threatened a woman in a Portland State University library.  Authorities say the library was evacuated after a number of people reported the man threatened the young woman last night.  Portland police say no one was injured and no gun was actually seen.  Authorities describe the suspect as a man in his 20s, wearing a black beanie, black pants, and shoes with white heels or soles.  The library was reopened by 7:50 last night.