Police said material seized from the computer of Pekka-Eric Auvinen suggests the 18-year-old had had Internet contacts with Dillon Cossey, 14, who was arrested in October for allegedly preparing a possible attack at Plymouth Whitemarsh High School in Pennsylvania.
"I consider it quite possible that he has been in contact" with Cossey, Det. Supt. Rabbe von Hertzen told The Associated Press.
He declined to provide details saying the investigation was on going.
Auvinen killed six students, a nurse and the principal in a high school shooting spree Wednesday in Tuusula, about 50 kilometers (30 miles) north of the Finnish capital, Helsinki. He then shot himself in the head, and died hours later at a hospital.
The discovery of the submarine has unveiled a few "inconsistencies." For example, how can one explain the fact that the sub was found where it needed to be searched for from the start?
When on a state visit to Singapore, Russian President Vladimir Putin promised to revisit the discussion of the 1956 Declaration between the USSR and Japan regarding the issue of the peace treaty with Japan
The TurkStream, which runs along the bottom of the Black Sea from Russia's Anapa to Turkey, will consist of two lines, each with a capacity of 15.75 billion cubic meters of gas a year