United Airlines has suspended a pilot who charged that Hillary Clinton should be “hung” for her use of a private email server as secretary of state.

In a tweet sent Sunday, the airline said it was “appalled” by the comments from Michael Folk, who also serves as a Republican member of the West Virginia House of Delegates.

This pilot has been removed from flying pending our investigation. We are appalled by his threatening comments. https://t.co/H1teA2nqsj — United (@united) July 17, 2016

United has also launched an investigation into Folk’s comments, which he made Friday on Twitter. In a tweet that has since been deleted, Folk said that Clinton should be tried for “treason, murder, and crimes against the US Constitution…then hung on the mall in Washington, D.C.,” according to the Associated Press.

Folk told the AP in a Sunday interview that he was being hyperbolic and could have stated his point “a little bit better.” He said his tweet was “clearly” not meant as an actual death threat against the Democratic presidential candidate.

The West Virginia Democratic Party urged Folk to resign from the House of Delegates over his remarks, according to Bloomberg Politics.