The friend, identified as Rauno, talked to a Finnish magazine about Matti Saari, 22, The Telegraph reported. He said Saari talked 18 months ago about a mass killing but he assumed it was a joke.

"He rang and announced in a perfectly calm voice that he had shot 10 people at the school and he was calling to say goodbye," Rauno said. "He said that he was going to kill himself and he wanted his body cremated afterwards."

Saari carried out the massacre this week at a vocational school in Kauhajoki.

In 2006, Saari was reportedly thrown out of the Finnish army because his shooting during a training exercise in the woods frightened other recruits. He lasted only a month in the service.

Saari is also reported to have been friends with Pekka-Eric Auvinen, 18, who carried out a similar massacre in Jokela in November, which also ended in suicide.