I just wanted to find my brother and get out.” What happened that day — already known in Iran as “Bloody Friday” — is by far the deadliest government crackdown against protesters since demonstrations began sweeping the country nearly a month ago.Internet service has been cut or severely disrupted in the region over the past two weeks, along with the cellular network, making it difficult to piece together how the violence unfolded.The Post interviewed two witnesses to the Sept. 30 crackdown, including the young man, who described security forces using deadly and indiscriminate force against peaceful demonstrators.But the protesters, many of them ethnic Baluch — a minority group that lives mostly in southeast Iran and across the border in Pakistan — had local motivations as well.He warned that the government crackdown “was further exacerbating the risk of continued turmoil.” After the initial shooting around the police station, security forces also fired on crowds gathered around the Makki Mosque, a short distance from the Mosalla."