and then return home to make it look like he was home that night to receive a phone call from joseph mcstayve that, yes. >> how strong is that proof? how reliable is the evidence gathered at the mcstay house weeks after investigators say they were murdered there? >> tons of critical evidence could have been lost in those first 15 days. >> 15 days when at least four people were in and out of the house. >> so many things in there that could have been relevant to the case. >> investigative journalist steph watts. >> we don't know if somebody in that house was related to or had knowledge of the crime could have removed items that could have been significant to solving this case. could have removed items that could have indicted them in this case. >> i don't think that you can seal a home for that long unless you are actually investigating a murder, and at that time, it wasn't. >> we know that the family members went in and out and susan mcstay cleaned the counters and she couldn't stand the house was dirty. she threw out dirty diapers. and mike mcstay took the video card out of the laptop compu