Try page 6...
Nice bits all over from walmarts own investigation:
"The final report that was sent to Walmart in December 2004 omitted references, contained in earlier versions, to MXN $45.6 million (approximately USD $4 million) paid to one of the gestores that Mexico Subsidiary Lawyer A alleged was corrupt."
Then there pieces where it talks about how the invoices are just lump sums rather than properly broken down and employees are claiming the the money is being given to the MX government officials..
"Investigator circulated a report concerning the Mexico Subsidiary allegations that stated that laws had been potentially violated, and recommended several additional investigative steps."
"Walmart did not follow the investigators’ proposed action plans. On or around February 7, 2006, Walmart tasked Mexico Subsidiary Lawyer B with leading the remainder of the investigation."
Of course none of this is going to be an email that says "hey this contractor is paying the government to speed up our permits, lets keep doing business with them."
No its all just looking the other way and doing the minimum to follow the letter of the law and using back channels to cut out the really incriminating parts.