Search warrants say Daye told responding officers Mangum stabbed him and took his money.
He died days later at Duke University Hospital.
She was initially charged with assault with a deadly weapon with intent to kill inflicting serious injury, but now faces a murder charge.
Funeral services for Daye will be held Tuesday at 1 p.m. at Union Baptist Church.
Daye, a Durham native, worked for Scotts Painting and Decorating Company at the time of his death.