A father and son became trapped while working in a grain silo in northwestern Wisconsin and didn’t get out alive, authorities said Sunday.

The incident occurred Saturday evening in the silo on the family’s farm along 17½ Street south of Barron, according to the Barron County Sheriff’s Office.

Daniel Briel, 51, and David Briel, 14, were identified as the people killed. A third person escaped the “internal collapse of silage ... and called 911,” a Sheriff’s Office statement read.

The Fire Department used thermal imaging devices and extrication equipment to free the father and son. Lifesaving efforts at the scene proved to be in vain.