Sisters Sita (18) and Rita (17) from Dhaulpur in Rajasthan and 15-year-old Ritu from Modinipur in West Bengal went missing from Ashray Sadan NGO situated near Taras temple in Vrindavan on Sunday, Deputy Superintendent Anil Yadav said.
The incident came to light when the girls were found missing while taking attendance in the ashram, he said.
"A love letter and a letter from Sita stating that she should not be searched as she is going on her own has been found," Yadav said.
The letter was written in Bengali and penned by Datapanni, Ritu' brother. Her father is working with R K Mission Ashram Vrindaban, he said.
We have informed Ritu's father and her brother is being interrogated, they added.