First elections in Brazil are mandatory, people tend to vote on the "least worst" candidate, or in the one they remember more from ads.
Second, elections in Brazil don't have vote re-counts, when you input a candidate in the electronic pooling stations, they just add a "+1" to some variable, or at least this is what they should do, the government don't allow third parties to examine the stations, so there is no way to know what they are really counting.
Finally, in lots of nearby countries there has been elections with similar results (members of Forum de São Paulo winning with around 51 or 52% of the votes) and the same company took care of the elections in all those countries.
On the other side, this same electronic devices are in use since 1996, thus all elections ever since fall under the same suspicion (even the one won by FHC).
The problem is that political parties only act when they are loosing. Now, the losers claim the devices can be tampered with... of course they can. But why didn't they make these devices right when they were in power?
that is not my point, and I has always been against the electronic ballots, I don't trust election results of any election since the electronic pooling stations, I am only more distrustful at these elections, because of the other things I mentioned (several friends of PT winning with 51%, the same company working on all those elections, some cities where people proved there was outright fraud, for example in one city people found memory cards and voter lists in the trash) and because of the popularity pools (before, and after the elections Dilma was unpopular, only DURING the elections her popularity suddenly rose... I don't believe people are THAT stupid)
1: https://en.wikipedia.org/wiki/Brazilian_general_election,_20...
Edit: it's actually pretty neat BTW. My state offers and online system and I can get done with the justification in less than 5 minutes.
