The formal identification of the victims of Finland's college massacre could take at least two weeks because their bodies were set on fire after being shot in their exam room, police said today.

This remote town in western Finland is in a state of shock, still trying to understand what had pushed Matti Saari, a 22-year-old trainee chef, into murdering 10 fellow students in the local catering and tourism college yesterday.

Saari had been quizzed by police on Monday over YouTube videos showing him firing his Walther P22 pistol at a woodland shooting range. They had no legal reason to detain him, however, and the officer in charge of the case decided not to suspend his handgun permit.

But a police spokesman said today that Saari would have been held had a more incriminating video in which he made an explicit threat of violence – "You will die next," he declares in English before firing his gun repeatedly (see above) – surfaced earlier.

That video was not posted on YouTube but on a Finnish social networking site, from which it was copied and disseminated via file-sharing sites after the killing started.

"The officer made his decision, he thought there was no reason to take the gun off him," said the spokesman, Mintala Urpo. "The only video we saw was where he was shooting at the range. It was only afterwards that much more information came out."

Mr Urpo refused to say whether the officer in question had been suspended but said that a person believed to have acted as Saari's cameraman was being sought.

In the meantime, this sleepy town, surrounded by lakes and forests, is trying to come to terms with the tragedy. The college where the massacre occurred was sealed off this morning behind police tape and guarded by soldiers from the Finnish army.

It has been closed until Monday but a steady a stream of pupils, dressed mostly in black, were arriving during the day to leave candles and messages for their lost friends.

Heidi Viittanen, who studies at a nearby school, said that she had heard nothing about her best friend since the shooting spree yesterday. "My friend was in the same classroom but I just don't know anything. I don't know if she's dead or alive."

Of Saari's 10 victims, all but one were in a room set aside for exams. Police said that Saari set off petrol bombs after the shooting, leaving the bodies charred beyond recognition. The nine corpses - seven females and two males - have been taken to the capital, Helsinki, for analysis.

The other victim, a young woman, was shot in the corridor outside and is thought to have died at Tampere University Hospital, where Saari himself died of self-inflicted head wounds yesterday afternoon.

Tapio Varmola, the college principal, today described Saari as a "silent young man" and said that nobody had any inkling about his deadly plan. "I am very depressed at the moment," he said. "He was a young man with two faces."

Times Recommends

• Plan for 9/11 trial in New York divides the city
• Beijing gets the jitters as Obama flies in
• Potshot Palin settles scores