From my transcription of Gray Hughes' interview with Becky Patty:
Part 1 Excerpt
Monday morning
They slept in ‘cause they were up late. When they got up it was, I don’t know, maybe 10:00 or so and Derrick made them pancakes. They had pancakes, and of course Libby always wants to be on the go and she was wanting to do something but Kelsi had to work that day.
...
So they came out and were doing some filing – they were out with the file cabinets, filing and stuff – and Kelsi came out – see, I don’t know the exact time of that, you know, why would we have paid attention to that – but she came out – it was probably close to 1:00 and said, “Hey, I work at 4:00. I’m going to go to a friend’s house for a little bit and then, then I’m going on to work. Well, as soon as Libby heard that, Libby jumped up and said, “Hey, will you take us to the bridge?” and Kelsi said, “I don’t care”. And she looked at me and said, “Grandma, can I go?” and I said, “Well, you’ve got to have a ride home ‘cause I’m working and I can’t stop to pick you up, you know, until quitting time and I’m not – I just don’t have the time to do it”. So she said, “Well, I’ll just call my Dad”. Well, I assumed that she called her Dad. I didn’t specifically say, “Libby, did you call your Dad?” I assumed it was done.
...
I assumed that everything was okay when she came and said, “Hey, we’re leaving”. She called her Dad on the way but it’s because she knew that he would never tell her “No”. He ne…, Derrick never told her “No” for anything, not that she ever asked for anything unrealistic but if she asked him to do something, he just, he did it. It’s just that – and if he would have said, “No”, I guess she would have come back home – Kelsi would have just brought her home – but there was no reason for him not to. He was taking these pictures, about 3 miles out of his way to swing by and pick her up. So it wasn’t big deal for him to swing by and pick her up. And they did. That’s when they left.
Part 2 excerpt
So they left here right around – give or take a couple of minutes – they left here right around 1:30. What I do know is Kelsi had said that she was talking on the phone to her boyfriend when she dropped them off, and I looked at phone records and it shows that she called or the call came in from her boyfriend at 1:38. So she was talking to her boyfriend at 1:38 when she dropped them off. That’s when the phone call started. So I don’t know how long she talked to him and I don’t know how many minutes it was to get there, but she dropped them off and she watched them. She said she watched them until they got to the, into the trailhead and then she pulled on out and went on to her friend’s house.
IN - Abigail (Abby) Williams, 13, & Liberty (Libby) German, 14, The Delphi Murders 13 Feb 2017 #104
Part 2 appears on the same page