The unexpected death of American Idol alum Mandisa is under investigation in Tennessee, but police do not believe it was suspicious, RadarOnline.com can confirm. The gospel singer was found dead at her home in Franklin on Thursday evening, and the Davidson County Medical Examiner confirmed her identity over the weekend. The Franklin Police Department sent RadarOnline.com an exclusive statement Monday afternoon that said: “At this time, there is no indication the death was the result of suspicious or criminal activity.” The department said it was continuing the “active death investigation” and …