NEW YORK (CNN) -- The wife of accused swindler Bernard Madoff pulled $15.5 million out of a Madoff-related brokerage firm in Massachusetts in the weeks before his arrest, authorities there disclosed Wednesday.

Bernard Madoff is under 24-hour house arrest in his Upper East Side luxury apartment.

The withdrawals by Ruth Madoff took place in November and December, according to a complaint filed by state regulators against Cohmad Securities, a firm they said was "intertwined" with Madoff's New York-based company.

The regulators say Cohmad has refused to provide information about its ties to Madoff, who is accused of running a Ponzi scheme that may have cost investors up to $50 billion.

Daily wire transaction reports show Cohmad was aware of transfers to and from Madoff-related accounts, the filing states.

"For example, the few reports produced by Cohmad show that Ruth Madoff withdrew $5.5 million on November 25, 2008 and withdrew $10 million on December 10, 2008," investigators said.

Bernard Madoff, 70, was arrested December 11 and is currently under house arrest in his Manhattan luxury apartment. He faces one charge of securities fraud in connection with an international scheme that has cost some investors their life savings and could face up to 20 years in prison and a $5 million fine if convicted.

In January, prosecutors tried to revoke his $10 million bail after he mailed more than $1 million worth of diamond-studded jewelry to friends and family, a move they said showed he was trying to move assets out of government hands. But a judge ruled Madoff was neither a danger to the community nor a flight risk.

Prosecutors and Madoff's lawyers have agreed for a second time to push back the deadline for an indictment or probable cause hearing for the former investor, sources close to the case said Wednesday. The previous deadline of Wednesday -- which was itself a delay -- has now been moved back another 30 days.

Madoff and the Securities and Exchange Commission already have agreed to a partial civil judgment against the disgraced investment manager, one that could eventually force him to pay fines and return investors' money.

Under the terms of the deal, Madoff will keep a previously reached agreement to freeze his assets and not to violate any other securities laws, but it does not require him to admit or deny any allegations.

CNN's Allan Chernoff and Amy Sahba contributed to this report.

All About Bernard Madoff • John Malkovich