The Milliyet newspaper said a forensic medicine lab will examine samples from Sierra's fingernails as well as hair and other samples from a blanket found near her body.
As Der Spiegel reported last week, veteran journalists Ahmet Sik from the far-left Radikal newspaper and Nedim Sener from the highbrow Milliyet journal were among those rounded up.
"Don't think that there are serious problems with the programme and that Fischer has come to solve them, " Michael Deppler, the IMF's European department director, told the Milliyet newspaper on Friday.