Indiana Republican Party leaders have stopped Senate candidate Richard Mourdock's campaign from using an important tool after allegations surfaced that the Tea Party challenger tried to improperly access a GOP database of voter information.The story has become another lightning rod in the heavily watched race between Mourdock and longtime incumbent Richard Lugar, who has held the seat since 1977.From The Indianapolis Star: At issue is a March 14 email obtained by The Associated Press in which Mourdock campaign manager Jim Holden writes that Mourdock staffers should “start pillaging email addresses” from a voter database known as Salesforce, which is used by all Indiana Republicans. A Republican official familiar with the problem told The Associated Press the Mourdock campaign's access to Salesforce was revoked shortly after the email was discovered. The official spoke on condition of anonymity because the investigation is ongoing.While GOP leaders are trying to keep the matter "in house" the Lugar campaign has pounced on Mourdock since the investigation was launched.