Durham Police watch commander Lt. B. Reitz told ABC11 that the 32-year-old Mangum's boyfriend, 46-year-old Reginald Daye, died at Duke University Hospital. He had been there since April 3.
Police say Mangum stabbed Daye in the chest during an argument at the apartment the couple shared in the 3000 block of Century Oaks Drive. Search warrants issued last week say Daye told responding officers Mangum stabbed him and took his money.
She was initially charged with assault with a deadly weapon with intent to kill inflicting serious injury. Police say more charges will likely be filed against her.
"The case remains under investigation and we do anticipate upgrading the charges," said Durham Police Department spokesperson Kammie Michael.
Mangum remains in jail.
Mangum made national headlines in March 2006, when the then NC Central student and exotic dancer claimed three Duke Lacrosse players sexually assaulted her during a performance at a team party inside a house near Duke's campus.
A year later, Attorney General Roy Cooper exonerated the players saying there was no credible evidence in the case.
Former Durham district attorney Mike Nifong - who pursued the charges against the players - was later disbarred and was accused of withholding DNA evidence that would have cleared them.
Mangum went into hiding, then graduated from NCCU in 2008 with a degree in police psychology. Later that year, she released a memoir, "The Last Dance for Grace: The Crystal Mangum Story".
Then last year, Mangum was arrested and charged with attempted murder, arson and child abuse after a domestic dispute with a man she dated before Daye.
In December, the jury found Mangum guilty of child abuse, but they couldn't agree on a first-degree felony arson charge, which could have landed Mangum in jail for seven years.