Regardless of what happens, Stern has vowed to make sure Arthur does not get custody of the baby. The sources also told TMZ that Stern would "do whatever is necessary to assist Larry Birkhead to defeat Virgie Arthur."
Regardless of today's outcome, the legal questions surrounding Smith's death and her family are likely to continue. An inquest into the death of her 20-year-old son Daniel was put on hold last month pending a legal challenge filed by Stern.
Daniel Smith died in a Bahamian hospital room from an apparently accidental overdose of methadone and two prescription drugs -- Zoloft and Lexapro -- that, when combined with methadone, can be deadly.
The chief magistrate overseeing that inquest has said that Anna Nicole Smith's mysterious death, just five months after her 20-year-old son's equally suspicious death, increased the police's interest in Howard K. Stern, who was present or nearby when both mother and son fell ill and died.
Anna Nicole's death "caused us to lose the weight of her evidence, but at the same time, it has also increased the interest in [Daniel's] inquest because of the way in which she died,'' Bahamian Chief Magistrate Roger Gomez told United Press International. He said the court will "look with interest at the cause of [Smith's] death as well.''
Gomez said that Stern's testimony is critical because "he would have been the only other person present at the time.''
Dozens of witnesses are expected to testify at the inquest whenever it resumes.
Additional reporting by Chris Francescani, and some information taken from wire reports.