MUMBAI/VISAKHAPATNAM: M Siva Theja, a 26-year-old PhD student from IIT-Bombay who had gone missing last week, was found dead under mysterious circumstances at a lodge in Visakhapatnam, Andhra Pradesh, on Saturday.

Police found his body in a decomposed state in the bathroom of one of the lodge rooms, his face covered with a thick polythene sheet taped at the neck. All his fingers had also been taped, and a roll of plastic tape was found lying near the body, police said.

His parents, residents of Hyderabad, had come down to Mumbai last Wednesday after he went missing and had been staying at the IIT-B's Powai guest house. They rushed to Visakhapatnam, also known as Vizag, after they received a call from the local police on Saturday, an IIT official said.

The family has a couple of relatives in Visakhapatnam, the official said.

Though the police are probing the suicide angle, they have not ruled out the possibility of murder.

Sources said death may have been caused by suffocation, and the post-mortem report did not indicate poisoning. However, the viscera has been sent for analysis.

A team of Vizag police will visit Mumbai soon, said Vizag police commissioner B Shivadhar Reddy.

One of Theja's relatives in Vizag, YV Ramireddy, said the boy was sensitive and an introvert.

IIT-B officials and students said they were shocked. Theja had spent many years on the campus as he had completed his B Tech and M Tech from there before starting work on his PhD.

Usually, PhD students go on trips or for interviews without informing anybody, so they were expecting him to return, an official said.

"He did not show signs of depression. He had recently helped the head of the electrical engineering department in organising a conference. He was a bright student and was about to complete his PhD by this summer," said Urjit Yajnik , dean of students' affairs.

The department will hold a condolence meeting at 5 pm on Tuesday. ( Inputs by Sulogna Mehta and V Narayan )