Send $2 million in Bitcoin or state employees will die, an anonymous letter threatened Gov. Gretchen Whitmer.
The letter was sent from an Indiana address in mid-December.
An investigation by Michigan State Police determined the threat was not credible, and no arrests have been made.
"The Michigan State Police takes very seriously any threats made against elected officials or others," a state police spokeswoman said in a statement. "Upon being notified of this letter by the Executive Office in mid-December, we looked into it. Part of that review included consulting with the Michigan Intelligence Operations Center. Ultimately, it was determined not to be a credible threat."
State police declined to divulge details of the letter.
The death threat came nearly three months after state and federal authorities arrested more than a dozen men accused of plotting
to kidnap Whitmer.
A bomb threat last week prompted the temporarily closure
of the state Capitol building.
Stay on top of Detroit news and views. Sign up for our weekly issue newsletter delivered each Wednesday.