Domenico Maurantonio, from Padua, died after falling from the fifth floor of the Da Vinci hotel in the early hours of Sunday morning.
Investigators are looking into whether it was an accident or if he was pushed, TGcom reported. But it unlikely that he committed suicide, the website said.
A coroner's examination on Sunday found bruising on the body, possibly caused before the fall, although the actual cause is yet to be determined.
Maurantonio, who attended Padua's Ippolito Nievo high school, reportedly went out drinking with friends on Saturday night, but not excessively, the TGcom said.
A minute of silence was observed at the school on Monday.
Head teacher Maria Grazia Rubini told students that "one thing we can be certain of" is that the fall wasn't voluntary.
"We need to wait for the judge to give clarity," she was quoted by Il Messaggero as saying.
"But we must pull together like a family, and mustn't let anyone discuss theories that are unfounded or incompatible with Domenico, who, as everyone can confirm, was a quiet, mature and reliable boy."