From Gary Slick:
On the basis of what we know so far, here is the sequence of events starting on the afternoon of election day, Friday, June 12.
* Near closing time of the polls, mobile text messaging was turned off nationwide
* Security forces poured out into the streets in large numbers
* The Ministry of Interior (election headquarters) was surrounded by concrete barriers and armed men
* National television began broadcasting pre-recorded messages calling for everyone to unite behind the winner
* The Mousavi campaign was informed officially that they had won the election, which perhaps served to temporarily lull them into complacency
* But then the Ministry of Interior announced a landslide victory for Ahmadinejad
* Unlike previous elections, there was no breakdown of the vote by province, which would have provided a way of judging its credibility
* The voting patterns announced by the government were identical in all parts of the country, an impossibility (also see the comments of Juan Cole at the title link)
* Less than 24 hours later, Supreme Leader Ayatollah Khamene`i publicly announced his congratulations to the winner, apparently confirming that the process was complete and irrevocable, contrary to constitutional requirements
* Shortly thereafter, all mobile phones, Facebook, and other social networks were blocked, as well as major foreign news sources.