The prosecution can't lie to the court, then try to mitigate that lie later. They are compelled to answer truthfully. If you look at the entire case as we understand it, then add what happened today, it makes sense they didn't/don't have squat in direct evidence. They even specifically said they had no video of anything happening to Heather. And they definitely have no confession. What they have is an affair, a lot of drama swirling around the case and the parties involved, a lunatic scorned wife, a lot of social media ranting and gossip, emotional text messages, a vehicle traveling toward PTL where a car was found, and then coming back from that direction, and a missing girl.
I'm sure the circumstantial details include more, but these defense attorneys are going to have a field day with this.