A letter from the Bihar police special branch asking officials to gather information on the Rashtriya Swayamsevak Sangh (RSS) and its affiliates has triggered a row between chief minister Nitish Kumar’s Janata Dal United and his ruling partner BJP.

The letter from the police intelligence wing directed the officers concerned to gather details like names, addresses, phone numbers and professions of officer-bearers in the RSS and 18 allied organisations and submit them as a report within a week.

The letter, which has been leaked, was sent to all deputy superintendents and district special branch officers on May 28, when futile power-sharing negotiations between the BJP and the JDU were going on at the Centre.

As a controversy broke, Nitish, whose jurisdiction includes the police since he handles the home department too, called a meeting of the force’s top brass at his 1 Aney Marg official residence.

Later, J.S. Gangwar, additional director-general, special branch, the wing that had issued the letter, held a media conference to announce that a probe had been ordered.

“The letter has been issued under the signature of a superintendent-rank officer recently promoted to the IPS. He is currently under training at the police academy in Hyderabad. We are going to examine the entire matter and will ask him why he processed such a file and did not seek permission from his superiors,” he said.

Gangwar said that neither the police headquarters, nor the home department or the sate government had asked the officer concerned to take such a step. “We will decide about action against the officer after the probe is complete,” Gangwar added.

The BJP had sought a reply from the state government while asserting there was no question of compromising its links to its ideological mentor.

“Media persons are asking us about the letter on the RSS. The state government should give a statement on it,” Sanjay Mayukh, MLC and the BJP’s national media co-head, said while raising the issue in the legislative council on Wednesday.

Party MLAs Nitin Navin and Sanjay Saraogi expressed “extreme objection” to the letter and said they would “never compromise about the RSS and its ideology, whether the government stays or goes”.

The power-sharing negotiations in May had ended in failure after the BJP offered just one cabinet berth to the JDU, which refused to accept it on the ground that sharing of power should be proportionate to the number of Lok Sabha seats won.

The JDU won 16 seats in the parliamentary elections and the BJP 17, the two accounting for the bulk of Bihar’s 40 Lok Sabha seats. Ally LJP of Ram Vilas Paswan won six seats and the Opposition Congress one.

Nitish expanded his cabinet soon after and offered one berth to the BJP, which declined it. The developments, combined with the JDU’s opposition to issues like a uniform civil code, triple talaq, and the citizenship bill, created stress between the allies.

The JDU has 69 MLAs in the 243-member Bihar House and the BJP 54.

Apart from the RSS, the police letter listed the Vishwa Hindu Parishad, Bajrang Dal, Hindu Jagran Samiti, Dharm Jagran Samanvay Samiti, Muslim Rashtriya Manch, Hindu Rashtra Sena, Rashtriya Sevika Samiti, Shiksha Bharti, Durga Vahini, Swadeshi Jagran Manch, Bharatiya Kisan Sangh, Bharatiya Mazdoor Sangh, Bharatiya Railway Sangh, Akhil Bharatiya Vidhyarthi Parishad, Akhil Bharatiya Shikshak Mahasangh, Hindu Mahasabha, Hindu Yuva Vahini and the Hindu Putra Sangathan.

A senior BJP leader said the timing of the letter raised “doubts about the intentions of our ally”.

“It’s a serious matter because it had ditched us once in 2013, without any fault from our side,” the leader told The Telegraph.

The RSS appeared unperturbed. “Our organisation is not an underground one,” RSS north Bihar province chief Pramod Kumar Agrawal said. “Everything about us is published and put in the public domain. What’s wrong if Nitish wants to gather information about us?”

Some RSS insiders made fun of the letter, saying the special branch had listed only 18 allied organisations when in reality there were over 140 such outfits.

The Opposition RJD said the letter was a welcome move by the Nitish government to keep tabs on the RSS.

“Nitish has seen the RSS from very close quarters,” senior leader Bhai Virendra said. “He knows what the RSS does and how. If he has deployed the special branch to keep tabs, it’s a welcome step because they are not nationalist organisations. They want to disintegrate the nation.”