The Portland police on Thursday explained their decision to reopen an investigation into accusations that former Vice President Al Goremade unwanted sexual advances toward a masseuse at a Portland hotel in 2006. In a release, the department said that there were “procedural issues,” including a lack of “command-level review,” when detectives interviewed Mr. Gore’s accuser in 2009. That interview came after several failed efforts to interview her by the police shortly after the incident is supposed to have occurred.