Escalating one of the investigations into President Trump’s inaugural committee, federal prosecutors ordered on Monday that its officials turn over documents about donors, finances and activities, according to two people familiar with the inquiry.

The subpoena seeks documents related to all of the committee’s donors and guests; any benefits handed out, including tickets and photo opportunities with the president; federal disclosure filings; vendors; contracts; and more, one of the people said.

The new requests expand an investigation prosecutors opened late last year amid a flurry of scrutiny of the inaugural committee. And they showed that the investigations surrounding Mr. Trump, once centered on potential ties to Russia during the 2016 presidential election, have spread far beyond the special counsel’s office to include virtually all aspects of his adult life: his business, his campaign, his inauguration and his presidency.

In the subpoena, investigators also showed interest in whether any foreigners illegally donated to the committee, as well as whether committee staff members knew that such donations were illegal, asking for documents laying out legal requirements for donations. Federal law prohibits foreign contributions to federal campaigns, political action committees and inaugural funds.