Let me correct my typos: They needed to do high-tech stuff, for hours and hours, to hit on a suspect. But simply checking the will at the outset would have pointed to the stepmother.
No, it's even easier. My husband and I called it as soon as we saw the "mother" even before we knew she was a stepmother only we got the motive wrong... we thought she and the husband were having an affair but we knew she was evil.
And since I'm married to an engineer type I love the lab rat thing. I actually think he's more of a Moulder type although a bit older and chunkier.