In a latest stint of threats and attacks in Bangladesh, a Ramkarishna Mission staff in Dhaka has received a threat letter allegedly sent by the militants. The mission authorities have on receiving the threat letter filed a complaint with the Wari Police Station, reports the Daily Star. Meanwhile, security has been beefed up at the mission. A countrywide mass crackdown has been launched by the government in the wake of rising attacks in the regio. So far, the authorities have detained over 11,000 people, mostly warranted criminals.