The Committee to Protect Journalists called on the government of the Indian state of Uttar Pradesh to immediately release journalist Siddique Kappan and drop any investigation into him. Kappan was arrested yesterday while traveling from the capital Delhi to Hathras district in Uttar Pradesh to report on a story, according to The Hindu and NDTV.

According to K.N. Ashok, editor of Malayalam-language news website Azhimukham where Kappan is a regular contributor, Kappan was travelling to Hathras to cover the alleged gang rape and murder of a 19-year-old woman from a marginalized community that has sparked protests and national outrage.

According to NDTV, Kappan and three others he was traveling with were detained at a toll plaza in the city of Mathura in Uttar Pradesh. The police accused the four of being members of the Popular Front of India, a Islamic fundamentalist group, and possessing “suspicious literature, one that could have an adverse impact on peace,” according to The Hindu.

“Police in Uttar Pradesh must stop obstructing journalists from reporting on a matter of national importance,” said CPJ’s senior Asia researcher, Aliya Iftikhar. “Authorities should immediate release Siddique Kappan and allow him to do his job.”

Ashok told CPJ that yesterday morning, Kappan informed the outlet that he was traveling to Hathras to report. Yesterday evening Ashok found that Kappan’s phone was switched off when he tried to reach him.

Uttar Pradesh police haven’t clarified the exact nature of the investigation into Kappan, nor have they identified where Kappan is being detained or informed his family or colleagues, according to a habeas corpus petition filed today by the Kerala Union of Working Journalists in the Supreme Court, which CPJ has reviewed. Kappan is the secretary of the Kerala Union of Working Journalists in Delhi. The Union has also written a letter to Prime Minister Narendra Modi and Uttar Pradesh Chief Minister Yogi Adityanath, which CPJ has seen, demanding Kappan’s immediate release.

Kappan was arrested shortly after the Uttar Pradesh government initiated 19 police investigations into claims that there is a “conspiracy to defame the state government” and instigate caste-based violence over the alleged gang rape and murder in Hathras, according to The Hindu.

On October 2, privately-held news channel India Today accused Uttar Pradesh authorities of illegally tapping the phone of its reporter Tanushree Pandey and leaking the recording of her conversations with the victim’s family on social media to intimidate her. Pandey broke the story of Uttar Pradesh authorities cremating the body of the alleged victim in Hathras without informing the family on September 29.

From October 1 to 3, local authorities in Hathras barred journalists from entering to prevent “meddling in the [government] investigation,” according to the Telegraph newspaper. Police stopped journalists Barkha Dutt of Mojo Story, a YouTube news channel, and Pratima Mishra and Manoj Adhikari of ABP News, a privately-held news channelfrom meeting the victim’s family and forcefully escorted them out of the area, according to ABP News and Dutt’s Twitter account.

Awanish Kumar Awasthi, additional chief secretary with the Uttar Pradesh government, did not immediately respond to CPJ’s request for comment over messaging app. Hitesh Awasthi, director-general of police in Uttar Pradesh, did not immediately respond to CPJ’s text message requesting comment.