A team of forensic experts visited Udayan Hostel on Nirmal Chunder Street in Bowbazar and collected samples from the spots where Irshad Alam, a TV mechanic, was allegedly lynched on Friday morning.

Senior officers from the detective department of Kolkata Police and the local police station accompanied the team. They collected samples from the first-floor rooms where a section of students had allegedly dragged the 37-year-old and beat him up on suspicion that he had stolen a mobile phone.

Hours later, he died in a city hospital with multiple injuries.

“The team members have collected samples from floors, walls and even stairs. They said they will send us a report shortly,” a senior police officer said.

“The forensic report is crucial in the case because of the preliminary post-mortem report.”

Alam died because of excessive internal bleeding, the preliminary post-mortem report said.

“There were bruises all over the body. The left shin bone was fractured and two fingers of his left hand had dislocated bones. He had a massive haematoma on his back, below his waist,” the officer said.

“The forensic report will be a vital tool for us.”

Alam was beaten to death on suspicion that he had stolen a mobile phone from a resident of the hostel.

According to the police, the prime suspect had reported a day before the alleged lynching that his phone was missing.

The police have arrested 14 residents of the hostel. All the accused, aged between 21 and 28, have been charged with murder, kidnapping and criminal conspiracy.

Some of the accused claimed innocence saying they were not involved in the violence. But when asked why they did not alert the police when the victim was being assaulted, they failed to give a satisfactory reply, an officer said.