Bihar police have arrested six persons from near the Indo-Nepal border here in connection with the killing of five persons last month, an incident dubbed as a “caste war” by the media and “massacre” by the Opposition.

All the six persons, including the alleged mastermind Praveen Jha, were arrested from a village in Bisfi police station area on Wednesday, said Madhubani superintendent of police Satya Prakash.

Those arrested were allegedly involved in gunning down five persons, including four brothers, belonging to the Rajput caste, in a village under Benipatti police station on March 29.

Prakash maintained that the incident that took place on Holi had followed a dispute over catching fish from a pond. However, some media reports said the mass killing was a fall out of a protracted struggle for supremacy among the two dominant castes — Brahmins and Rajputs — in the area.

The Opposition RJD had latched on the issue to train its guns at the Nitish Kumar government and claimed that the police was trying to “shield” the killers since they enjoyed the patronage of a powerful local BJP leader.

The Opposition party, which was often criticised for massacres carried out by rival Maoist groups and private armies of landlords while it ruled the state, has contended that the “carnage” in Madhubani was proof that “jungle raj” prevailed in Bihar.

RJD leader Tejashwi Prasad Yadav, who had earlier this week travelled to Benipatti to console the family members of the deceased, exultingly posted on Twitter that “police announced the arrests just 10 minutes ahead of a press conference where we were going to expose the collusion between the administration and the perpetrators. This is the power of the opposition”.