Tesla said on Tuesday that the Justice Department had requested documents from the company after its chief executive, Elon Musk, abruptly announced that he had lined up funding to convert the publicly traded electric carmaker into a private company.

The request for information suggests the Justice Department has opened a preliminary investigation into Musk’s market-moving Twitter post on Aug. 7 about the potential buyout.

The Justice Department inquiry, along with an intensifying Securities and Exchange Commission investigation into Tesla’s practices and communications, substantially increases the risks facing the embattled company. Tesla already is under intense financial pressure, with its shares down 25 percent since early August, and the government investigations introduce the possibility of costly penalties or other sanctions.

Tesla said in its statement Tuesday that it received the Justice Department’s request last month and “has been cooperative in responding to it.” The company released the statement after Bloomberg News reported that federal prosecutors had begun an investigation.

The Justice Department inquiry is being handled by the U.S. attorney’s office in San Francisco, according to a person familiar with the matter. It is unclear whether the inquiry is criminal or civil or whether it is at such an early stage that the question has not been settled.

While the specific scope of the Justice Department inquiry isn’t known, prosecutors in investigations like this one might look at a company’s accounting practices, the adequacy and accuracy of its public disclosures and whether executives had sought to mislead investors.

Tesla said the Justice Department’s request was not a subpoena but rather a “voluntary request for documents.” The company added: “We respect the DOJ’s desire to get information about this and believe that the matter should be quickly resolved as they review the information they have received.”

Investigators in the SEC’s San Francisco office are examining whether Tesla misled investors about its production goals. They also are looking into Musk’s tweet, in which he said he had “funding secured” to take the company private for $420 a share.

The tweet blindsided Tesla’s board and ignited a rally in Tesla’s shares. It soon became clear Musk had not nailed down the billions of dollars in outside funding that would be required for such a deal. Nor had he retained any banks to assist in the fundraising process.

Musk said later in August that he was shelving the idea of converting Tesla into a private company.

As part of the investigation, the SEC in the past month has sent subpoenas not only to Tesla but also to financial institutions it hired to explore the going-private transaction, according to people briefed on the subpoenas. Goldman Sachs and Silver Lake, a large investment firm, both received subpoenas demanding materials about their interactions with Tesla, the people said.

It is not clear whether the Justice Department inquiry is, like the SEC’s, focused on a wide range of issues at Tesla or in particular on the circumstances surrounding Musk’s Twitter post. Musk and the company he helped found have been bouncing from crisis to self-inflicted crisis in recent months.

There have been severe production problems at Tesla’s California plant, and the company is burning through its cash at a rapid clip. Musk has faced off with many short-sellers, who are wagering that Tesla’s shares will fall. The company’s chief accounting officer resigned after a month on the job. Musk appeared to smoke marijuana during a recent video interview. He was sued this week by a British cave rescuer whom Musk accused of being a pedophile.

As the pressure mounts, Musk has retained his own lawyers to represent him in the government investigations, separate from the law firms hired by the company and its board.

Lawyers from Hughes Hubbard & Reed — including Roel C. Campos, a former SEC commissioner — are representing Musk in connection with the SEC investigation, according to three people familiar with the arrangement. Musk has also hired Steven Farina, a partner at Williams & Connolly who specializes in government investigations and accounting malpractice, to represent him, two of the people said.

A request for documents from a U.S. attorney’s office would often be a sign of a criminal investigation. But federal prosecutors sometimes proceed with civil, not criminal, cases. They generally do so when the conduct they are investigating does not clearly violate a criminal statute or when prosecutors’ main goal is to stop someone from a specific type of behavior. Lawsuits also carry a lower burden of proof than criminal cases.

The news of the Justice Department inquiry sent Tesla’s shares down more than 3 percent on Tuesday.