Katko v. Briney, was a court case decided by the Iowa Supreme Court, in which two homeowners (Edward and Bertha Briney) were held liable for battery for injuries caused to a trespasser (Marvin Katko) who set off a spring gun set as a mantrap in an abandoned house on the homeowners’ property. The case thereafter received wide attention in legal circles, becoming a staple of tort law casebooks and law school courses.
Bertha Briney inherited an old farmhouse in Mahaska County, Iowa, which the Brineys had left vacant for the last ten years prior to the incident. They had the farmhouse boarded up and placed “No Trespassing” signs around the property. The farmhouse was in poor condition and was subject to frequent burglaries and break-ins.