Deputies found Kostial's body on Saturday morning while on routine patrol.
Thousands of protesters have opposed the construction of the Thirty Meter Telescope at Mauna Kea's summit, a site considered sacred by Native Hawaiians.
When Florencio Millan-Vazquez refused to leave his vehicle unless U.S. Immigration and Customs Enforcement officers showed him papers, they smashed his window.
There were no injuries, but the bridge over the Goose River near Northwood, North Dakota, collapsed, the sheriff's office said.
The law carves out exceptions for veterinarians who perform the procedure to treat a cat's existing infection, disease or injury.