Clarence Thomas accepted a free yacht trip to Russia and got flown out on a complimentary helicopter ride to Putin's hometown, 2 Democratic senators say

• Democratic senators have accused Justice Clarence Thomas of accepting undisclosed gifts and trips.
• They say he accepted gifts such as a yacht trip to Russia and a chopper ride to Vladimir Putin's hometown.
• The senators want an investigation into potential tax fraud and ties between Thomas and Harlan Crow.

Two Democratic senators have accused Justice Clarence Thomas of accepting a free trip to Russian President Vladimir Putin's hometown.

Sen. Sheldon Whitehouse of Rhode Island and Sen. Ron Wyden of Oregon filed a letter to US Attorney General Merrick Garland on July 3, asking to open an investigation into the Supreme Court judge.

The letter said there was a "serious possibility of tax fraud" and accused Thomas of having "secretly accepted gifts and income potentially worth millions of dollars."

The letter's appendix , which lists 35 undisclosed gifts, shows a "yacht trip to Russia and the Baltics" and a "helicopter ride to Yusupov Palace, St. Petersburg," both listed under the year 2003.

St. Petersburg, Russia, is Putin's birthplace and where he grew up. The president now resides in Moscow.

The appendix list is titled "Likely Undisclosed Gifts and Income from Harlan Crow and Affiliated Companies." Harlan Crow is a real-estate developer and the former chairman and CEO of the Trammell Crow Company.

The senators cited a ProPublica report from May last year detailing Thomas' hushed-up financial ties to Crow.

The report said that apart from the Russia trip, Crow also funded Thomas' grandnephew Mark Martin 's boarding-school fees, which cost "more than $6,000 a month."

In their letter, the senators wrote that other gifts from Crow included "multiple instances of free private jet travel, yacht travel, and lodging," as well as "gifts of tuition for Justice Thomas's grandnephew," "real estate transactions," "home renovations," and "free rent for Justice Thomas's mother."

In September, Thomas said he'd accepted three trips on a private plane owned by Crow . He didn't mention any other gifts.

Whitehouse and Wyden aren't the only Democrats who've voiced concerns over Thomas' sketchy financial ties.

Rep. Alexandria Ocasio Cortez of New York filed articles of impeachment against Thomas and Justice Samuel Alito on Wednesday.

"Justice Thomas and Alito's repeated failure over decades to disclose that they received millions of dollars in gifts from individuals with business before the court is explicitly against the law," her statement reads.

Representatives for Thomas, Whitehouse, Wyden and Crow didn't immediately respond to requests for comment from Business Insider sent outside regular business hours.