A student who gunned down eight people in a Finnish school reportedly chatted online with a teenager accused of plotting a school attack in the US.
Police say Auvinen was consumed with anger against society
Pekka-Eric Auvinen discussed the Columbine school massacre and exchanged videos with Dillon Cossey, a lawyer for Mr Cossey told the Associated Press.
Material found on Auvinen's computer suggested online contact with the US student, Finnish police said.
They said they had not yet talked to US counterparts about the possible link.
Auvinen, 18, killed eight people and fatally wounded himself at the Jokela High School in Tuusula last week.
Police arrested Mr Cossey, 14, last month for allegedly preparing an attack at the Plymouth Whitemarsh High School in suburban Philadelphia.
They found a rifle, 30 air guns, swords, knives, a bomb-making book, videos of the 1999 Columbine massacre and violence-filled notebooks in his home, the Associated Press reported.
Mr Cossey's lawyer, J David Farrell, said on Monday that his client did not encourage Auvinen "in any way".
"They had discussed certain video games and shared videos with each other," he said.
"Obviously, Columbine was a shared topic of interest."
Mr Farrell said his client was "horrified" when he found out about the massacre in Finland.
"He had no indication that somebody he was communicating with actually was formulating an intent to commit a violent act."
US police said they were looking into reports of contact between the two teenagers, but could not confirm a link.
Also on Monday, Finnish police said a suicide note that Auvinen left, in which he explained his hatred towards society, is believed to have been written on 5 November, two days before his killing spree.
Auvinen gave a warning of the shooting in a video posted on the internet.