Deepmoni Saikia, who was picked up last evening from among protesting junior doctors and students demanding justice for murdered student Sarita Tasniwal, was arrested during the day, Dibrugarh Superintendent Rana Bhuyan said at a press conference.
Saikia who was arrested on circumstantial evidence, however, denied the charges, Bhuyan said.
A ward boy of the hospital, Kiru Mech, who was produced before the media, detailed how he and Saikia allegedly killed Tasniwal on Friday.
On the day, a nurse claimed to have seen Saikia in the hospital around 5.30 am when she was signing off from duty, the SP said.
Mech alleged that Saikia strangled Tasniwal when she was sleeping in a restroom in the hospital, put phenyl in her mouth and slit her throat with a surgical knife.
"Saikia did not give me any reason for the murder, but asked me to cooperate if I wanted my job to be made permanent," he alleged. Saikia then took away Tasniwal's mobile phone, he said.
A missed call from Saikia at 9:00 am the same day was found in Tasniwal's phone, the SP said. Records of phone calls between the two medical students for one month before April 24 were also found, he said.