He "was very distressed" to learn of the violence, Farrell said.
Montgomery County District Attorney Bruce L. Castor Jr. is taking a second look at material on Cossey's home computer.
The chief superintendent detective of the Finnish Central Criminal Police, who is overseeing the investigation, said officers were sifting through a lot of "technical information" to find links with Cossey. "We're going to look at what he has uploaded, what kind of sites he has visited, and what kind of contact he's had with other persons," Jan-olof Nyholm said by phone yesterday.
Pekka-Eric Auvinen, 18, of Tuusula, gunned down six students, a nurse and the principal at his high school, about 30 miles north of Helsinki.
Cossey told Farrell that in the e-mails, Auvinen "gave no indication he was going to do anything violent," and that Cossey "offered nothing in the way of encouragement." He learned of the incident from his attorney.
Cossey and Auvinen shared an interest in a video game series called "Hitman," Farrell said, adding that they may also have had a mutual obsession with Eric Harris and Dylan Klebold, the students responsible for the 1999 Columbine High School massacre.
Nyholm said the two may have visited the same Columbine-related sites, which the Finnish official said are routinely monitored by U.S. law enforcement for hints of potential copycat plots. The Finnish Central Police is equivalent to the FBI, said a spokeswoman for the Finnish embassy.
Online games enable players to reenact school shootings. In "Super Columbine Massacre RPG!", gamers assume the roles of Harris and Klebold during the shooting spree. A more recent game, "V-Tech Rampage," puts players in Cho Seung-Hui's shoes as he guns down students at Virginia Tech.
"Hitman," which has reportedly sold more than 10 million copies, involves a genetically engineered, ruthless assassin known as Agent 47. A movie version is in the works.
Farrell said he believed more information about the timing and extent of the contact between the two teens would be available today from Castor.
The district attorney said he expected to have information from the forensic analysis of Cossey's computer "to determine if the screen name from the suspect in Finland comes up."
Police seized the computer Oct. 10, along with a 9mm semiautomatic carbine, knives, live homemade grenades, BB guns, swords, violent videos, and a bomb-making manual. Cossey, a home-schooled student who admitted to his plans to attack Plymouth Whitemarsh High School, is awaiting a hearing to determine his treatment program, which could last until he turns 21.
His parents took Cossey, an overweight youth, out of school because of incessant taunting and bullying.
Michele A. Cossey is awaiting a Dec. 13 preliminary hearing on charges stemming from her son's gun possession.
"I doubt whether this new information, even if true, would have much effect on our prosecution, but it could be helpful to the authorities in Finland to explain the conduct there," Castor said.
Both Castor and Farrell said they had not been contacted by Finnish police. FBI spokeswoman Jerri Williams said Castor asked the agency to use its "international contacts" to help determine the communication between the two teens.
"There appears to be a cadre of people who idolize Klebold and Harris from the Columbine massacre, of which Cossey was one, and perhaps the person in Finland is another," Castor said.
The day before Auvinen's attack on Wednesday, the 18-year-old posted a YouTube video detailing his plans.
The next day, he played a last round of "Battlefield 2," his favorite online game, then walked to Jokela High School, where he killed the victims before turning the gun on himself.
Police initially described him as being from "a very normal family. . . . He had no problems at school," but they said he had an interest in dark online fantasy games.
Farrell said that he had reviewed Internet material that "glorifies violence and deifies Klebold and Harris" and that his client had agreed to speak to officials about his "violent fantasies."
"I thought he could assist by helping professionals understand the dynamics of alienation and peer abuse," Farrell said.
Cossey's postings revealed a fascination with violence, but not a promotion of it, Farrell said. "Is it surprising that kids absorb the violence that we throw at them?" Farrell asked.
But while critics say video games trivialize tragedy, some enthusiasts see them as a way to engage issues underlying school shootings. A message on the Web site Manifesto Games, where "Super Columbine Massacre RPG!" is available for download, said the game is "insightful, somber, and respectful of its material."
An online forum about the game invites gamers to reflect on school shootings. Some posts discuss the killers' motives, while others tell stories of being bullied at school. An Oct. 22 message written by a gamer identified only as "Nic" thanked the creator for providing an alternative to real school violence.
"I just avoided that road 2 months ago, but now I'm just deciding to thank you for creating this to steer me in the right direction," the post said.
According to an FBI report, adolescent violence has decreased since 1993, a statistic out of sync with public perception.
"The sudden, senseless deaths of teenagers and teachers in the middle of a school day, for no comprehensible reason, is far more shocking and gets far more attention than the less extreme acts of violence that happen in schools every week," said the report, by Mary Ellen O'Toole, the supervisory special agent at the FBI's National Center for the Analysis of Violent Crime.
The report identifies several misconceptions, including the fact that the school shooter is always a loner or is motivated by revenge.
"Many adolescents are fascinated with violence and the macabre, and writings and drawings on these themes can be a reflection of a harmless but rich and creative fantasy life," it said.
Contact staff writer Kathleen Brady Shea at 610-701-7625 or firstname.lastname@example.org.
Inquirer staff writer Cheryl McEvoy contributed to this article.
Go to http://go.philly.com/bullying for a video report on the link that authorities said existed between the two, plus previous coverage of Cossey.