Two young adults, Mahakdeep Kaur, 21, and Davinder Singh, 22, were arrested in Punjab in connection with the Sri Ganganagar railway track blast case.
The blast happened about 75 minutes after a passenger train had passed, damaging the track.
Investigators say Kaur may have been influenced by handlers from Pakistan who used promises of love and money.
Mahakdeep Kaur suspected of ISI links
Police believe Mahakdeep Kaur was working with handlers known as "Chacha" and "Shah," suspected to be tied to Pakistan's ISI.
Three others were also picked up for helping with things like transport and accommodation.
During the operation, police recovered two weapons, 46 cartridges, and 30,000 rupees from Mahakdeep Kaur.