REDWOOD CITY, Calif. – When Scott Peterson’s mistress Amber Frey takes the stand for cross-examination today, the defense is expected to ask embarrassing questions about bad relationships and play secretly taped recordings that prosecutors withheld from the jury, sources said.

In the previous few court days, as prosecutors played Frey’s recordings of her conversations with Peterson, 31, in the weeks after the Dec. 24, 2002 disappearance of his pregnant wife, Laci, pundits suggested that Geragos should go light on Frey during his cross-examination.

They noted that Frey, a 29-year-old single mother of two, came off as a very credible and sympathetic witness, a good citizen who dedicated herself to helping police gather evidence which might show that Peterson caused Laci’s death.

But Geragos offered several signs last week that he was preparing an arsenal for his cross-examination of Frey:

* Upon the conclusion of Frey’s direct examination on Tuesday, after private hearings with attorneys, San Mateo Superior Court Judge Alfred Delucchi made it obvious that Geragos wanted to discuss many details of Frey’s love life.

Delucchi said that, in response to Geragos’ request, he was allowing Geragos to discuss only those relationships that Frey mentioned in the tapes played in court – of which there are several. In one of those relationships, Frey lived with a man who was married to a pregnant woman.

* Although attorneys were tight-lipped about what caused Delucchi to postpone Frey’s testimony from that morning to today, most trial observers are convinced that the delay stems from efforts by Geragos to introduce wiretapped recordings not played by the prosecution.