doing it. i can imagine morgan doing it. i don't know what they were thinking. >> figuring out what they were thinking was now the job of the county prosecutor, and it would prove to be more complicated than expected. >> did she say you need to go dig a hole? >> morgan had pointed the finger at steve, but now he was back and about to tell a very different version of event. >> on the day of the murder she's texting him, has the poison worked yet? when it is not working yet she says, couldn't you just pick up a shovel. >> the truth? well, that takes us right back to where our story began. the tale of the texts has another chapter to come. >> coming up -- who was the mastermind, morgan or steve? when "dateline" continues.