Crystal Mangum, 32, allegedly stabbed live-in boyfriend Reginald Daye, 46, with a kitchen knife during an April 3 argument.
Daye died at Duke University Hospital Wednesday night after being treated for serious torso injuries, police said.
"More than likely, we will be upgrading the charge to murder," Durham Police Chief Jose Lopez Sr. told The (Durham, N.C.) Herald-Sun.
Mangum was initially jailed on a $300,000 bond and charged with assault with a deadly weapon with intent to kill. A man calling 911 after the alleged stabbing identified Mangum as the attacker, police said.
Magnum was arrested in February 2010 and charged with attempted murder, arson and child abuse after an argument with Milton Walker, her then-boyfriend.
She allegedly attacked Walker and set his clothes on fire in the bathtub while three children were present, police said.
She was found guilty in December of three counts of child abuse, injury to personal property and resisting a public officer. A felony arson charge was dismissed.
In March 2006, Magnum, who is black, falsely accused three white Duke University members of the men's student lacrosse team of raping her at a March 13, 2006, party held at the house of two team captains.
Fallout from the case's resolution included the disbarment of Durham County District Attorney Mike Nifong, the lead prosecutor.