NEW YORK – Federal authorities will charge at least two employees from disgraced financier Bernard Madoff’s former firm in the coming weeks — and Madoff’s brother and two sons could be next, two people familiar with the probe into Madoff’s financial fraud told The Associated Press.

Madoff’s brother, Peter, and sons Andrew and Mark — executives in the Madoff firm’s legitimate market-making and proprietary-trading business — are likely to face tax fraud charges later this year, but may escape more serious securities fraud charges if authorities fail to come up with solid evidence they knowingly participated in the massive fraud, the people said.

The people, who asked not to be identified because the investigation hasn’t been completed, declined to name the two employees or specify possible charges.

Four other employees and an outside accountant already have been charged with helping Madoff pull off a multibillion-dollar Ponzi scheme that spanned decades and burned thousands of investors.

The 71-year-old Madoff is serving a 150-year prison term after admitting that his secretive investment advisory service at Bernard L. Madoff Investment Securities never bought any securities.

Instead, he created phantom wealth by using new investments to pay returns to existing clients.

There was no response to requests for comment Friday from lawyers for Madoff’s brother and sons. The Madoffs have vehemently denied wrongdoing in past bankruptcy court filings and in their attorneys’ statements.

Although it doesn’t specify the tax crimes the family could face, a criminal complaint filed in February against Madoff’s operations chief, Daniel Bonventre, implicates Madoff relatives without naming them.

Under Bonventre’s watch, it says, the firm “extended more than 15 loans, totaling over $50 million, to Madoff family members and key employees” for the purchase of luxury homes, and “purported to forgive most of these loans after a few years.”

The firm, it adds, also “made millions of dollars in payments directly from the Ponzi Scheme Accounts to Madoff, family members and certain employees, including Bonventre. These payments were separate and apart from payments made through the payroll system. “

Bonventre has pleaded not guilty to charges he banked nearly $300,000 in undeclared income derived from the fraud.

The 16-month Madoff investigation is grinding forward, with FBI agents still camped out on the 17th floor of a Manhattan skyscraper that once was home to Madoff’s financial empire.

The agents and prosecutors also continue to cultivate Frank DiPascali, a chief Madoff aide, as their star cooperator.

As part of a plea deal, DiPascali’s “continued cooperation” has been of “substantial assistance to the government in its investigation and prosecution of others,” prosecutors wrote in a February letter to a federal judge in Manhattan.

Federal authorities have said in the past that Madoff’s wife Ruth probably won’t be prosecuted because – unlike her sons and brother-in-law – she had no official position or responsibility in the business.