West Lafayette police are trying to figure out why fliers threatening singer-songwriter Jackson Browne and “college liberals” wound up tied to storm doors and bundled on driveways near Purdue University neighborhood.

Police received multiple complaints and picked up at least 50 fliers that called for Jackson Browne to get it “Bam! Right between the eyes.” The fliers were rolled up with two or three sheets. In some cases, they were nailed and delivered a few blocks away from Purdue’s Mackey Arena, according to the Journal-Courier.

The unsigned, uncredited fliers also issued a warning to college liberals, saying “its Trump time now, shut your mouth or pay the consequences.”

The fliers are similar to ones that surfaced last month ahead of a Jackson Browne concert in Windsor, Ontario. In that case, the fliers called on Canadians to exercise U.S. 2nd Amendment rights and “shoot a socialist.”