On April 18, 1812, The Republican Advocate in Batavia, New York carried an article warning that an "armed British and Indian force"  was ready to invade from the Canadas. The article speaks of the "Prophet's band" which refers to Tenskwatawa, the brother of Tecumseh the great Shawnee leader. The brothers were working to establish an independent American Indian nation east of the Mississippi. In 1811-12 Tecumseh had traveled widely in the south to recruit tribes to this confederacy. Tenskwatawa was the religious leader whose ideas led to a native religious revival calling for a return to ancestral ways and a rejection of European ways, including European clothing and alcohol. Tecumseh was the military leader of the armed resistance having been born and reared in violence he was a formidable warrior. Tecumseh sought alliances with various tribes and, when war came, with the British. The fears of the colonists had been heightened by a number of attacks in the frontiers. American colonists believed that the British were instigating these attacks. These fears are expressed in the article of April 18th:
We stop the press to announce the intelligence of an armed British and Indian force on the Canada side of the Niagara river, apparently with an intention to make a descent on the American side. It is stated that the Indians are receiving supplies of arms and provisions from the British military stores at Newark; and that boats are in readiness to transport their men across the river.
We learn that intelligence has been transmitted to Messrs, Porter and Barton from some of their friends in Upper Canada stating that it is advisable for them to remove their families from the rivers.
A messenger has been sent express from Lewistown on Niagara river to Gen. Hall of Ontario county, to call out the militia immediately. The companies in this place are embodying to march at a moment's warning. Indian Agent B.F. Stickney writes to Indian Territorial Gov. William H. Harrison to inform him that "twenty-four of the Prophet's band had passed this place, in the last of February, for Fort Malden, to receive ammunition which was promised to be ready for them. They returned on the 4th ... with as much gunpowder, lead and new [muskets] as they could carry.
1. My attention was drawn to this article by the reference in the very interesting Bicentennial of the War of 1812 website operated by U.S. Navy which can be found here.