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....