Life in Tehran has seemed pretty normal today, with some major exams taking place. But as this email to the BBC suggests, police states act with dispatch and secrecy:

"At about 1730 in front of Sa'di metro station, plain clothes officers were shooting, and I myself saw four people die. I was lucky to get away unharmed. How can they claim they are not killing anyone?" he wrote. He said he thought many people were being killed, wounded and arrested but they were all "taken away by plain clothes officers... there is no trace left of them, and obviously no news agency can report this".