(Bloomberg) -- A pair of Senate Democrats wants the Justice Department to investigate whether crypto exchange Binance Holdings Ltd. lied to lawmakers about its business practices.

Massachusetts Senator Elizabeth Warren and Chris Van Hollen, who represents Maryland, said in a letter to US Attorney General Merrick Garland that the crypto platform may have made false statements, including over whether its American affiliate Binance.US was truly a separate entity. In a 136-page complaint filed in federal court on Monday, the Securities and Exchange Commission alleged that the US firm and Binance’s global entity, which isn’t supposed to allow Americans to trade, weren’t actually independent from each other.

“This is a serious matter,” the lawmakers wrote in the letter to Garland on Wednesday.

Representatives for Binance didn’t respond to requests for comment. The Justice Department declined to comment.

Back in March, Warren, Van Hollen, and Roger Marshall, a Republican from Kansas, asked for information on the relationship between Binance and Binance.US. They also requested a range of financial data. In response, Binance said the two companies were “separate entities” and that it made compliance a priority. 

The responses were meant to inform Congress’s legislative process and “it appears that Binance and Binance.US undermined this important investigation and the legislative process by providing false and misleading information to Congress,” the lawmakers wrote in their Wednesday letter. 

Patrick Hillmann, Binance’s chief strategy officer, signed the firm’s 14-page response to the March inquiry, which described the company’s work to build out its compliance program but provided scant details on its finances.

Read more: Binance Answers Elizabeth Warren Without Addressing Financials

In its complaint, the SEC alleged that Binance and its Chief Executive Officer Changpeng Zhao violated a number of securities rules, mishandled customer funds and misled investors. 

The SEC also said the international company and Zhao were “intimately involved” in directing the US-based business. The SEC has sought a temporary restraining order to freeze some assets as part of its case. 

Previously, state regulators in Texas also raised concerns about the independence of Binance and Binance.US from each other.

On Thursday, Warren emphasized that she wanted Binance to be held accountable. “It is a crime to lie to Congress,” she said in an interview with Bloomberg Television. “I want the Justice Department to take a look.”

--With assistance from Tyler Kendall.

(Updates with Warren comment on Thursday in final paragraph.)

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