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.

Paul Walsh • 612-673-4482