(CNN) -- The sisters of an Iowa politician were found shot to death at their Pennsylvania home last week, according to Pittsburgh police. The bodies of Sarah and Susan Wolfe -- the sisters of Iowa state Rep. Mary Wolfe -- were found in their basement Friday after officers were sent to the home to check on the well-being of one sister when she didn't show up for work. Each died of a single gunshot wound to the head, and their deaths were ruled homicides, the Allegheny County medical examiner's office said Monday. On Facebook, Mary Wolfe thanked those who had extended their sympathies, saying the family was "heartbroken, but grateful." Mary Wolfe is the oldest of eight children, according to her website. Police haven't identified a motive for the shootings. A car belonging to the women was missing but was recovered early Saturday, police said.
NEW: Each died of a single gunshot wound to the head, medical examiner's office says . Two sisters of Iowa state Rep. Mary Wolfe were found shot to death Friday . Pittsburgh police haven't identified a motive for the shootings .