“There’s no question” that a probe into Joe Biden’s son Hunter Biden appears politically motivated, Sen. Mitt Romney told reporters Thursday, adding, “I think people are tired of these kind of political investigations.”

Romney, a member of the Senate Homeland Security and Governmental Affairs Committee, could block an upcoming subpoena planned by committee head Sen. Ron Johnson (R-Wis.).

Romney said he’d meet with Johnson to “see what information he has” before deciding whether to back a subpoena. “I would hope if there’s something of significance that needs to be evaluated, it be done by the FBI or some other agency that’s not as political as perhaps a committee of our body,” the senator said.

Johnson initiated a probe of Ukrainian energy company Burisma and Hunter Biden, who joined Burisma’s board when his father was U.S. vice president. President Donald Trump’s personal attorney Rudy Giuliani has accused the Bidens of illegal actions linked to Burisma without offering any details, substantiation or evidence.

Trump was impeached after withholding military aid from Ukraine while pressuring the country’s president to launch a probe into unfounded accusations against the Bidens. The former vice president’s recent uptick in the Democratic primaries has rekindled threats of an investigation by the Senate.

Johnson told Fox News on Wednesday that the investigation was not politically motivated. He hopes to subpoena a former Ukrainian Embassy official who worked for a Washington-based consulting firm that Burisma hired to combat accusations of corruption. Romney’s vote against the subpoena would result in a deadlock, blocking the action.