A 56-year-old sub-inspector with the Railway Protection Force was killed allegedly by an RPF constable in Thane district, an official said on Thursday.
Basavaraj Garg, posted in Ambernath town, was found dead in his barrack in Kolsewadi in the Kalyan area around 10 p.m. on Wednesday, as per Assistant Commissioner of Police, Kalyan, Umesh Mane Patil.
The suspect, Pankaj Yadav (35), posted at Roha, was detained, he said, adding that a probe was on to ascertain the motive behind the killing.
According to a police release, Garg was alone in his barrack on Wednesday night as his roommate had gone out. He was listening to music when the accused barged into his room and allegedly attacked him with a wooden log and killed him, it said.
The body was later sent to a government hospital for post-mortem, the police said. The Kolsewadi police were conducting a probe into the incident, they added.