Agra, Oct. 7 -- Four students of Sanskrit, aged between 17 and 22, died after entering a water tank on the premises of Panini Gurukulam in Vrindavan on Tuesday night, Mathura SSP Shlok Kumar said. According to police, one of the students entered the tank after experiencing foul smell emanating from it. When he did not return, four other students went down one after another. While one of them was rescued, four others were found dead inside, the SSP said. The deceased belonged to Meerut, Vidisha, Kaushambi and Jabalpur. Police teams reached the spot and rushed the students to hospital. Four of them were declared brought dead. Police are investigating the exact cause of the deaths. District magistrate of Mathura CP Singh said the tank was 12-feet deep. "Presence of some poisonous gas may have been the reason," he added....