Federal agents have questioned friends and associates of Gov. Gavin Newsom of California and his wife, Mr. Newsom said on Monday in a video in which he accused President Trump of using the Justice Department to punish a political enemy.

The full scope of any investigation remains unclear. But Mr. Newsom’s aides say part of the federal investigation appears to focus on his wife, Jennifer Siebel Newsom. Former employees of the governor and people affiliated with his wife’s nonprofit groups are among those who have been questioned by agents, according to the governor’s office.

A person familiar with the investigations, speaking on condition of anonymity because they were not authorized to discuss the case, said there were multiple federal investigations underway related to the governor, including one looking at his wife’s finances. This person said the investigations were initiated by federal law enforcement officials in California, based on government witnesses offering information there, and were not launched by officials in Washington.

An F.B.I. spokesman declined to comment. A White House official referred all questions to the Justice Department.

“Donald Trump isn’t just coming after me because of my mean tweets,” Mr. Newsom said in the video. “He’s coming after me because I am considering running for president.” He added, “To get me, he’s coming after my wife.”

Mr. Newsom, a Democrat, described the investigation as a fishing expedition in which federal agents had started sifting through “years and years of random documents” and knocking on the doors of family friends and associates of the Newsoms to try to find evidence of an unspecified crime.

Several people associated with the Newsoms have been contacted by federal agents in the past week, according to the governor’s office. Mr. Newsom’s aides believe the agents have also subpoenaed banking records, but said they had seen no written evidence of that.

Ms. Siebel Newsom, who calls herself California’s first partner, is a documentary filmmaker whose work focuses on the social impacts of sexism. She founded a nonprofit organization called the Representation Project that advocates for gender equity, in part by developing educational materials based on Ms. Siebel Newsom’s documentaries.

Ms. Siebel Newsom also owns a film production company called Girls Club Entertainment. It is listed as a contractor of the Representation Project on the nonprofit’s tax returns. Tax records show that the Representation Project makes annual payments to Girls Club Entertainment. In 2024, the nonprofit paid Girls Club Entertainment $161,250 for film production work.

Ms. Siebel Newsom is also a co-founder of the California Partners Project, a nonprofit that works to get more women onto corporate boards, address the gender pay gap and make technology safer for children. Some of the donors that support the California Partners Project are groups with business before the state government.

For years, critics have raised the possibility of self-dealing, but no public evidence of wrongdoing by any of the entities tied to Ms. Siebel Newsom has surfaced, and it remains unclear what precise issues and actions investigators have been asking questions about.

Mr. Newsom has reported soliciting $4.3 million in donations to the California Partners Project since 2020, according to disclosures filed with the state’s ethics agency. That includes $1.8 million from a Native American tribe that has an agreement with the state to operate a casino in Sonoma County. In California, public officials must disclose donations to charities that are made at the official’s request.

Another nonprofit group with ties to Mr. Newsom is called the California Protocol Foundation. Its board includes some of Mr. Newsom’s top advisers during his time as governor and previously as the mayor of San Francisco. The foundation pays for initiatives that the governor says he does not want state taxpayers to cover, including his travel overseas for conferences and other meetings.

Mr. Newsom’s office said the investigation is a fresh attempt to smear him after the federal prosecution of his former chief of staff revealed no misconduct by the governor. The former chief of staff, Dana Williamson, pleaded guilty last month to three felonies in a sprawling corruption case.

One of the crimes Ms. Williamson pleaded guilty to was lying to the F.B.I. about information she had access to while working in Mr. Newsom’s office. In her plea agreement, Ms. Williamson said she gave her former business partner confidential information about state litigation that involved one of their clients and then lied about it when questioned by the F.B.I.

The agreement does not name the client, but details in the indictment align with a sex-discrimination lawsuit that California regulators filed in 2021 against the video game maker Activision Blizzard. The company had been a client of Ms. Williamson’s consulting business before she joined Mr. Newsom’s office. In 2022, Mr. Newsom fired the state lawyer leading the suit against Activision, prompting complaints that he was interfering.

When Ms. Williamson was indicted last year, her attorney said that federal agents first approached her during the Biden administration. She was working for Mr. Newsom at the time, and the agents asked her if she would cooperate in an investigation of the governor. She replied that she had no information to give them because she had never witnessed any criminal conduct by Mr. Newsom.

Earlier this year, Mr. Newsom’s office responded to questions from Mr. Trump’s Justice Department about his 2022 termination of the lawyer involved in the Activision lawsuit, according to a spokesman for Mr. Newsom. Then the communication from federal officials ceased, the spokesman said.

The latest inquiries into associates of Mr. Newsom and Ms. Siebel Newsom began around the time Mr. Trump said that he planned to nominate Todd Blanche as attorney general, according to the governor’s office.

Mr. Blanche had previously defended Mr. Trump in three of the four criminal cases he was facing.

Nominated to be the number two official at the Justice Department at the beginning of Mr. Trump’s second term, Mr. Blanche — now the acting attorney general — has pursued prosecutions of Mr. Trump’s perceived enemies. He also signed an agreement granting the president and his companies immunity from audits of past tax returns to settle a $10 billion lawsuit the president brought against his own government earlier this year.

Mr. Newsom has been highly critical of Mr. Blanche’s nomination to the top Justice Department position, recently calling Mr. Blanche “the guy covering up the Epstein Files” and saying he “gave Trump and his family a lifetime pass to commit tax crimes.”

Mr. Newsom, in his video address, mentioned that Mr. Trump had called for his arrest last year and he said he was proud to join the “hit list” of people standing up to the president. He accused Mr. Trump of “selling the presidency” for golf course approvals, cryptocurrencies and a private jet, and pledged to continue calling out what he saw as corruption from the White House.

“You can subpoena my records. You can investigate me. You can harass me,” Mr. Newsom said. “Put my name on every and any enemies list you have, but leave my wife and family out of your personal vendetta.”