Rev. Knapp died of consumption.

The evidence

• “Knapp, but his connection with the Church was rendered uncertain and temporary by threatening ill health, and he was soon compelled to cease his labors. He died July 14, 1860, of consumption. Rev.”

  1879-history-of-rock-county/15-rock-county-ch09-beloit.md, PDF p. 639 / book p. 643

  Butterfield, C. W., et al. The History of Rock County, Wisconsin: its early settlement, growth, development, resources, etc. Chicago: Western Historical Company, 1879. Cornell University Library via the Internet Archive, archive.org/details/cu31924028871585.

  Grade A: Found on a page of one of our sources