“I believe it is an incredibly dishonest campaign tactic using half-truths and lies to intimidate voters from participating in the democratic process,” he said.

Morfeld said he began hearing from people who received the cards about a week ago. He said the ones he has seen were sent to people living in midsize Nebraska towns and cities, such as Norfolk, Grand Island and Geneva.

The address side of the cards said they were paid for by the Alliance for the Pure Life, a previously unknown entity that gave its address as a post office box in Norfolk, Nebraska.

No entity by that name has filed with the Nebraska Accountability and Disclosure Commission or registered as a corporation with the Secretary of State. Representatives of groups opposing the gambling and medical marijuana petitions said they had never heard of the new entity.

One side of the cards said: “Your private confidential information could be at risk when you sign any petition. Be alert.” The other side was topped by large letters reading “Official Warning.”