UPDATE: The StarTribune covers the story:
Minneapolis police say the unidentified man who stalked and raped a woman Saturday in northeast Minneapolis took steps that lead investigators to believe this might not have been his first offense.
"The fact that this individual concealed his identity by covering his head and took steps to destroy evidence and other particulars of the case lead us to the possibility he is a convicted sex offender," said Lt. Nancy Dunlap, head of the sex crimes unit. "All these things concern us."
The man broke into a vacant apartment around midnight Saturday and then got into the woman's apartment through a common wall, police said. He had watched the woman's apartment for a day or two to see if she lived alone, Dunlap said. The man also told the victim things to indicate he had targeted her.
From the 2nd Precinct:
Facts: On October 3, 2009, officers responded to a call. A lone female victim was at home in the 34xx block of Polk St. NE when a suspect broke in through a vacant attached apartment. The male appeared to have stalked and targeted his victim; he waited until she was alone and then sexually assaulted her.
Suspect information: The suspect is described as a white middle-aged male, six feet or taller, skinny, wearing a flat brim trucker hat, a flannel shirt long sleeve button down, and blue jeans. The suspect did take precautions to conceal his identity.