JEFFERSON CITY, Mo. (AP) — The Missouri Democratic Party says it will ask the U.S. Securities and Exchange Commission to review a mysterious donation to Republican Eric Greitens’ campaign for governor to determine if it violated “pay to play” rules.

Democratic state chairman Roy Temple slammed the donation Wednesday during a teleconference with reporters, and the party said in a statement that it would send a letter to the SEC calling for an investigation.

At issue is a $1.9 million gift to Greitens’ campaign from political action committee SEALs for Truth.

Greitens has said the super PAC is made up of military members. Public records show its only donor is a nonprofit whose contributors have not been disclosed.

Greitens’ campaign manager says the move by Democrats is meant to distract from issues about Democratic gubernatorial candidate Chris Koster.