None of the articles stated the dog led them to the spot she was found at. The handlers were not paid--they are a non-profit org funded by donations. Their travel expenses were paid. The PI wasn't working on the case at the time--and we don't know when he though Pala might be a good spot--if he ever thought that at all.
This article states
Around the Pala Mission, and for approximately three miles north on Pala Temecula Road, the dogs found Amber's scent in numerous locations, the handler said.
In the area Amber's remains were found, the dogs again followed a trail, Jones said.
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For three days, the two handlers, Bart, an Escondido police officer and a private investigator Welch hired followed the dogs. (according to this a PI WAS working the case)
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"The dogs were going crazy," she said. "Where they really went nuts was in the residential area across the street from the casino."
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Welch paid the team's expenses.
Handler Julie Jones said the two Labrador retrievers used in that search effort (Which was acting as the team leader, Platt or Jones, they are both in the media. Also, why would she say the two labs when they were not two labs?)
http://www.nctimes.com/news/local/escondido/article_7a7449b1-6a3d-5930-a68b-c0373e775ad1.html
Now, in the next article things change a bit
Sarah Platts of the VK9 Scent Specific Search and Recovery Unit told 10News that it took her dogs less than a day (as opposed to 3 days above)
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Amber Dubois family had hired Sarah Platts and the search team to look for Amber. (stating they were hired)
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The team worked there way to a spot that turned out to be near where Amber's remains were found.
quoted from
http://www.examiner.com/x-18953-San...ily-lead-searchers-to-Pala-last-August-photos
So, according to these articles, they may have been hired. They did trail up to where the body was found but missed it. The timing was anywhere from 1 to 3 days. There was a PI involved. There was a Escondido deputy with them. She was in the residential area near the casino.