UPDATE: Mistrial declared in Annette Cahill case

IOWA CITY, Iowa (AP) - 3/12/19: (KWQC) - A mistrial has been declared in the Annette Cahill case.

(AP) An Iowa grandmother will stand trial Monday in the 1992 beating death of her former boyfriend in a case built largely on an alleged confession heard by a child.

The trial of Annette Cahill will test the state's ability to get a conviction in an old homicide case in which investigators have no physical evidence.

Instead, the case may hinge on whether jurors believe a woman who says she was 9 when she overheard Cahill confess to killing bartender Corey Wieneke weeks after the slaying.

Cahill has pleaded not guilty to first-degree murder in the death of of 22-year-old Wieneke, whose body was found in his rural West Liberty home in October 1992. If convicted, she faces life in prison.

The 56-year-old Cahill is an unusual defendant. She has no criminal record and works for the Police Law Institute, an Iowa-based company that helps train police officers.