J. Lopez Gallardo, a Physics Professor at the University of Texas, claims that there is a perfect "Pearson Coorelation" in the preliminary "PREP" electoral results of Mexico's Presidential election.
This means that the results do not have the random variations we would expect from the reports from actual voting, and must have been generated by a computer simulation or algorythm. Such correlations can be a key sign of rigged elections, such as Iran 2009.
In the discussion on Gallardo's Twitter pages, another professor suggests that Gallardo may have summed the data incorrectly.
The "PREP" is a preliminary, electronic vote reporting system. It is used to transmit voting data from Mexico's polling places on election night, providing early results prior to a fully count. In 2006, there were multiple concerns that this system was manipulated to produce the appearance of a win for the right-wing candidate. That election was later contested on multiple grounds.
Mexico's Presidency was stolen via centralized fraud in 1988, and the same was claimed for the 2006 election.