It would definitely be good to know more about the ping. It sounds like it was very close in time to when SS said Kiely called her (12:33 vs 12:36). So I'd guess that's the event that created the final ping.
I'm far from an expert, but from doing some research it sounds like there are a number of events that can trigger a ping:
- any incoming or outgoing call/text/data use/etc
- any time a phone switches cell towers
- any time a phone enters airplane mode
- at a set interval (usually a number of hours)
Given that, I don't think we can confidently say that KR's phone was turned off/submerged at exactly 12:33. As long as she didn't use it and she didn't travel far enough to connect to a new cell tower, the phone would not have pinged. She could have stayed at the party for a while after the event that triggered the 12:33 ping.
What we can probably say is that she didn't drive far enough away to connect to a new cell tower. Or if she did, her phone was already off or in airplane mode.