I agree with this but also feel that MK waking up and spotting the perp was more significant. I think the investigation would have moved much slower without the intense media interest that resulted because of the Rachel alert going out. Perhaps the Jeep would have been back at the trailer park by the time authorities got around to talking to Rick. They may have never even known it had been to the garage at all.
As I said before, you have an excellent point about the jeep being key. My theory has been the "big score", since the bank robberies only netted about $600/perp. (The burglary gone wrong theory is thought to be the cops theory.) I think that there may be three possible scenarios:
1) Ricci's accomplice raped and/or killed the girl probably while Ricci was at work, accounting for Ricci's sour attitude when he returned the jeep.
2) Ricci acted alone and may have thought he could leave the girl in the jeep in a secure location - tied and gagged. Maybe she suffocated in the unseasonably hot June weather this year. This might account for why all the windows were open on the jeep when it was returned.
3) Maybe Ricci and his accomplice(s) decided to cut their losses after the sensational publicity. It became unrealistic to assume they could safely get a huge ransom after FBI involvement, nationwide publicity, etc.
There are several interesting questions I would like to have answers to: At the time the police interviewed Edmunds, they said he provided useful information. What was it? A few weeks after Ricci was arrested and the jeep was confiscated, there was a report that they had found blood evidence in it. We never heard any more about that. Whose blood was it?