Saari and Auvinen "Played Battlefield 2" Together: Internet Killer Network Fear

Matti Saari, 22, and Pekka-Eric Auvinen, 18, played on the same team in an internet war game called Battlefield 2 in which they detonated bombs, shot people and used headsets to communicate.

It was also revealed that Saari had been thrown out of the Finnish Army in 2006 after only a month when he terrified fellow recruits by opening fire against orders in a woodland exercise.

The killers also sent typed messages to each other on their computers talking about their plans for a school shooting. One of the messages said: "Let's do it together."

They even bought their guns at the same weapons store, called Tera-asekeks, a few hundred yards from a school in the town of Jokela, where Auvinen killed eight people and himself last November.

Saari waited 10 months before carrying out his rampage on Tuesday, killing 10 people and himself at the vocational college where he was studying to be a chef in Kauhajoki, 150 miles from Jokela.

A friend of Saari's, who did not want to be named, said: "My friend dated him but they broke up after Jokela. The reason was the messages he and Auvinen had been sending to each other."

Police fear Finland could now be facing a network of other potential school killers linked by the internet. A series of copycat threats were made at schools across the country and at least one school was evacuated.