David W. Guth tweeted "blood is on the hands of the #NRA. Next time, let it be YOUR sons and daughters." The NRA is the National Rifle Association, the country's top gun lobby. It has fought restrictions on the constitutional right to bear firearms.
Monday's shooting at a Navy base left 13 dead, including the gunman.
The University of Kansas says Guth, an associate professor of journalism, has been placed on indefinite administrative leave pending a review.
Chancellor Bernadette Gray-Little says the action was taken to prevent disruptions in the learning environment.