former wisconsin sheriff 's deputy andrew steele , 40 , has been found not legally responsible in the killing of his wife and sister-in-law .
he shot dead wife ashlee steele , 39 , and her sister kacee tollefsbol , 38 , on august 22 .
his defense team had argued that lou gehrig 's disease had damaged his brain , making him not criminally responsible for the deaths .
prosecutors believed steele had planned the killings abnd a third sister said he had displayed inappropriate feelings towards tollefsbol .