A southwest Missouri woman has pleaded guilty to fatally poisoning her husband and son with antifreeze and attempting to kill a daughter over a 14-month period.

The Springfield News-Leader (http://sgfnow.co/1lzFogv ) reports that 53-year-old Diane Staudte pleaded guilty Thursday to one count of first-degree murder, one count of second-degree murder and one count of first-degree assault.

Under the plea deal, Staudte, of Springfield, will avoid the death sentence. She faces a life prison sentence.

A medical examiner initially ruled that her husband's April 2012 death was from natural causes and that her 26-year-old son died of prior medical issues in September 2012. Those deaths were re-examined after Staudte's 24-year-old daughter, who had been poisoned, was hospitalized in June 2013.

Another daughter pleaded guilty earlier to helping her mother with the poisonings.