"The blatant disregard for the law that your PAC demonstrated is deeply troubling," the letter stated, referring to DeVos’ political action committee. "The PAC that you chaired failed to pay fines that were imposed on it over eight years ago."
All Children Matter, which DeVos leads, reportedly owes the state of Ohio $5.3 million for election-law violations.
Sanders sought the 2016 Democratic presidential nomination but represents the state of Vermont in the Senate as an independent. The other letter-writers were Democratic Senators Tom Udall, Sherrod Brown, Edward Markey and Jeff Merkley.