Emails between high-ranking Michigan state officials show they knew about an uptick in Legionnaires' disease and it could be linked to problems with Flint water long before Gov. Rick Snyder said he got information on the outbreak.

A spokesman for Snyder rejected the report by the liberal group Progress Michigan on Thursday. Emails obtained by the group show Snyder's principal aide, Harvey Hollins, was made aware of the outbreak and a possible link to the use of Flint River water last March.

Snyder said in January he had just learned about the rise in Legionnaires cases.