New York ? If Ruth Madoff hopes to hold onto her fancy apartment, her millions in cash and her jetsetting lifestyle while her husband is in prison, experts have some advice for her: Get ready for an inquisition.

Attorneys and investment specialists say Madoff will have a difficult time proving her assertion that up to $69 million of the couple’s wealth was unrelated to her husband’s Ponzi scheme.

“It’s going to be very hard for her to show that anything is untainted,” said Alton Abramowitz, national vice president of the American Academy of Matrimonial Lawyers.

Some angry investors suspect their money ended up in Ruth Madoff’s hands. At the court hearing where her husband pleaded guilty Thursday, the mere mention of her name drew jeers and laughter.

The couple met at their Queens high school and married in 1959, the year after she graduated. She was blonde and pert and devoted, and some investors have said their long marriage lent an air of stability to Madoff and his fund.

But even if she is never charged with a crime, Ruth Madoff’s wealth will be closely reviewed by federal prosecutors and civil lawyers.

Investigators will want to see personal bank statements, credit card receipts, tax returns and canceled checks, as well as her business records.

“The process gives us the right to look at all of it to try to prove that Mrs. Madoff did not earn this money on her own,” said Jeffrey Sonn, a securities specialist in Fort Lauderdale, Fla., representing dozens of Madoff claimants. “It’s intrusive, sure, but that’s the procedure.”

What those credit-card receipts will show is a life apparently unbound by care, with homes in Palm Beach, Fla., the south of France and the tip of Long Island, besides the $7 million penthouse in midtown Manhattan. There was also travel by private jet and yacht.