The family of Princess Hend al-Fasy, the ex-wife of Prince Turky bin Abdul Aziz, filed a report with the prosecutor's office in February demanding that the case be reopened, al-Masry al-Youm reported Thursday.
The family said it had reason to believe a crime resulted in her death at the Movenpick Hotel in Cairo.
Turky is the brother of King Abdullah bin Abdul Aziz of Saudi Arabia.
The family's report alleges a conspiracy among Hend's ex-husband, former President Hosni Mubarak, ex-Interior Minister Habib al-Adly and the hotel's manager to cover up the crime.
The family claims that days before her death, the princess accused Turky of attempting to murder her daughter, and alleges Hend was killed with a fatal morphine injection.
The family has also accused the Ministry of Interior of closing the initial investigation and forging the late princess's death certificate.