"Why did they stage the car? A cartel is not interested in staging anything," he said. "The bodies weren't that far off of the main road. A cartel wouldn't want bodies ever to be found, and they wouldn't be just 50 feet off the road. It looks like an amateur, and not a cartel hit."
Despite this new evidence in a perplexing case, Baker said he still doesn't feel any closer to finding out what happened to the McStays.
"No one ever looked at this with a criminal slant," he said "It's more of a mystery now. Who would kill an entire family, bury them, then stage the car?"
Baker has now asked Amazon.com to take his book off the market, and has promised to personally refund the purchase price for anyone who previously bought the book, because he saw it as a means to discovering what happened to the McStays.
"My conscience won't allow me to sell it -- the purpose was for awareness," he said. "Now that we know what happened, I can't sell one more book. I thought they were part of my family, and I grieved when I heard. The people who did this, the death penalty is too good for them. They should be tortured to death."
ABC News' Alyssa Newcomb contributed to this report.