MADISON, Wisconsin — A forensic psychiatrist has testified that Lou Gehrig’s disease affected the brain of a former Dane County sheriff’s deputy who killed his wife and sister-in-law.

Andrew Steele has pleaded not guilty by reason of mental disease in the shooting deaths last August of his wife, 39-year-old Ashlee Steele, and her 38-year-old sister, Kacee Tollefsbol, of Lake Elmo.

Taking the stand for the defense Wednesday, Dr. Doug Tucker testified that a message Steele wrote about suicide and sexual relations with his wife and sister-in-law is delusional and shows Steele had brain damage.