Commandant of 2nd Tripura State Rifles Tapan Debbarma was arrested last night in connection with Journalist Sudip Datta Bhowmik's alleged murder case on 21 November.
He is to be produced in the court today.
President of Tripura Journalists Union, Syed Sajjad Ali, speaking about the incident said, no one exactly knows what happened.
"Fact of the matter is that he was shot dead and we understand he was shot dead inside the chamber. He was fired in a meticulous way. Also, there were other follow up measure they took to hush up the evidence by taking away the body to a distance. His phone was also missing," Ali told ANI.
"Yesterday's incident is more horrific as it was executed by the security force," Ali added.
He also said it was "unfortunate" that this incident is not receiving coverage from the mainstream media.
"Unfortunately the incident has not made a dent in the national arena and mainstream media is quite reluctant to give it coverage," said Ali.
Sudip Datta Bhowmik was allegedly shot dead on Tuesday in Tripura's RK Nagar.
He was reportedly killed inside the battalion headquarters of Tripura State Rifles (TSR) in RK Nagar.
"Sudip's was a cold-blooded murder. He was killed inside the Circle Officer's room," Bhowmik's brother told ANI.
Earlier, on September 20, a journalist, Santanu Bhowmik, was killed allegedly while he was covering a road blockade agitation of the IPFT.
Another journalist, Gauri Lankesh, was shot dead point blank outside her residence on the outskirts of Bengaluru, Karnataka on September 6, triggering protests in many parts of the country.
It was said Lankesh was targetted for her work against right-wing Hindu extremism.