Her family said in a statement issued by WakeMed Hospital in Raleigh that Taft was attacked Saturday while staying at the Raleigh home of her boyfriend, who was in Florida at the time.
Police and Taft's family both said the 62-year-old Greenville woman died Tuesday.
Police spokesman Jim Sughrue says officers are now investigating the case as a homicide.
Taft has been on the state Board of Education since 1995.
She was reappointed to serve a second term until March 2011.
Taft ran unsuccessfully for a state Senate seat in 2008. Her ex-husband is Tom Taft, a former state senator from Greenville.