Microsoft founder Bill Gates spoke more than once with Jeffrey Epstein, the late financier accused of child sex trafficking, to discuss ways to increase philanthropic spending, according to people with direct knowledge of the matter.

Epstein's discussions with Gates included at least one meeting, which took place in New York in 2013, while Gates was still Microsoft's chairman, these people said. It was unclear whether the two also spoke on the phone.

The discussions with Gates occurred years after Epstein served a 13-month sentence for a charge of soliciting an underage prostitute. Epstein was sentenced in 2008 in Palm Beach County.

The revelation is another piece of the rapidly growing mosaic depicting Epstein's bizarre, confounding influence and ability to get into powerful circles. Gates' interaction with Epstein is puzzling because the former Microsoft CEO is one of the richest and most influential people in the world. Gates could get philanthropic advice from anyone, and yet he corresponded with Epstein, whose transgressions were well known at the time.

Gates resigned as Microsoft's CEO in 2000, stepped away from a day-to-day role there in 2008, and served as the company's chairman until February 2014. He remains on the board.

Epstein, a former friend of Presidents Bill Clinton and Donald Trump, died at age 66 over the weekend in an apparent jailhouse suicide weeks after the wealthy financier was arrested on federal charges of child sex trafficking.

The people with knowledge of the matter did not know the exact details of what was discussed at these meetings, except to say that they focused on "growing philanthropy" on a broader scale and that there were other philanthropic leaders in attendance. Gates never committed to helping Epstein with his own nonprofit organizations. Eventually, the Microsoft founder ceased communication with the disgraced financier.

The Bill & Melinda Gates Foundation, launched in 2000, has at least $32 billion in assets, according to the organization's 2017 tax filing. The foundation says it works to "ensure that all people — especially those with the fewest resources — can access the opportunities they need to succeed in school and life."

Gates has a net worth of over $100 billion, according to Forbes.

After the meeting in New York six years ago, Gates flew on one of Epstein's planes to meet with his family in Palm Beach, the people added. He did not, they noted, fly on the so-called "Lolita Express," which was allegedly used to transport underage girls to Epstein's home in the Virgin Islands. The Daily Mail first reported on Gates using the plane in March of that year, citing flight records.

A spokeswoman for Gates did not deny that the former Microsoft CEO met with Epstein. But she said that Epstein did not perform official financial advisory work for Gates.

"Epstein never provided tax, estate or services of any kind to Bill Gates," the representative said.

A spokesperson for Microsoft did not respond to a request for comment.

People who knew Epstein said he would tell associates that he did spend time with Gates — and that he acted as an informal advisor to him.