Kolkata, June 29 -- A security guard from the south Kolkata law college in Kasba, where a 24-year-old student was allegedly gang-raped on Wednesday evening, was arrested on Saturday. Two students - Zaib Ahmed (19) and Pramit Mukherjee (20) - and a staffer of the government-run law college, Monojit Mishra (31), were arrested on Thursday. "We have arrested a security guard of the college. This is the fourth arrest in connection with the case. The probe is ongoing," a senior officer said. Police said the alleged incident took place between 7.30 pm and 10.50 pm on Wednesday, when the woman had gone to the college to fill out some forms for an upcoming exam. The woman - who was allegedly the TMCP's women's wing secretary in the college - was asked by the accused to stay back for some discussions, she said in her complaint, which HT has seen. In the evening, Mishra allegedly proposed marriage, which she declined, stating that she had a boyfriend. The accused then allegedly tried to force himself on her. The victim had a panic attack and requested to be taken to a hospital. Mishra, however, allegedly refused to let her go. "He took me near the washroom and tried to force himself on me... I fought back," she said in the complaint. Mishra's aides, Ahmed and Mukherjee, allegedly locked the main gate of the college and forcibly took the victim to the guard's room. The security guard was allegedly asked to leave. In the guard's room, Mishra allegedly attempted to rape her. "Mishra instructed Ahmed and Mukherjee to take me to the guard's room and make the guard sit outside. They did so," she wrote in the complaint. Police have seized CCTV footage that showed the security guard loitering outside. He did not rush to help the victim or attempt to inform the college authorities or raise an alarm. The woman also sustained a head injury. She alleged that Mishra tried to hit her with a hockey stick. She was also allegedly shown a video clip that had been captured on a mobile phone by one of the accused while she was being stripped, the complaint said. She was threatened that the video would be circulated on social media. A day later, the woman informed her family following which she filed a police complaint at the Kasba police station. A medical examination of the woman was also conducted at a state-run medical college. In the complaint, she said that Mishra works as a criminal lawyer in the Alipore court in Kolkata. He is also employed as a contractual staff member at the college. "Mishra was recruited purely on a contractual basis around 45 days ago, on the directions of the governing body of the college. TMC legislator Ashok Kumar Deb is the president of the governing body," Nayna Chatterji, vice-principal of the college, told media persons. The Bharatiya Janata Party (BJP) alleged that the main accused in the crime - Mishra, a former student of the college....