certainly within the first few weeks of the murder. >> on the surface, there were haunting similarities. in april of 2010, 69-year-old delores was found stabbed to death in her burning home. >> she was known to leave her house open. she did not knock her doors. it could have been a stranger from the street. >> a few months later, 74-year-old joan davis, a well-known activist was found strangled and stabbed to death in her burning home. >> we had always believed that the person that murdered joan davis was someone that she let into the house. >> and now, rob cantor had been found dead in his burning home. >> very early on, we were looking at could rob cantor's killer be the same killer with miss davis. >> the answer was unclear at