This is a screen captured image taken from internet website YouTube of a teenage gunman, which features in a video posted by a man going by the username of Sturmgeist89, who is believed to be responsible for shooting dead at least seven people at a Finnish school Wednesday Nov. 7, 2007. An 18-year-old man opened fire at a high school in southern Finland on Wednesday, leaving at least seven people dead and 11 injured, officials said. Police said they had the situation "under control" after they surrounded the high school in Tuusula, some 50 kilometers (30 miles) north of the capital, Helsinki.

TUUSULA, Finland — The Finnish teenager who killed eight people in a high school shooting was a bullied social outcast but appears to have picked his victims randomly, a senior police official said today.

Investigators believe the gunman, identified as 18-year-old Pekka-Eric Auvinen, revealed plans for the attack in postings on YouTube in which he urges revolution, and grins after target practice.

"You can say that the motive is still open," Detective Superintendent Tero Haapala told The Associated Press. "But the explanation can be found mainly in his Web writings and his social behavior."

Police said Auvinen killed eight people before turning the gun on himself Wednesday at Jokela High School in Tuusula, some 30 miles north of the capital, Helsinki. Police initially said the victims were seven students and the principal, but Haapala said Thursday that the school nurse was among those killed.

He also said Auvinen appeared to have selected his victims at random.

"There's nothing that links him with the victims except that they attended the same school," Haapala said.

Auvinen shot the victims with a .22-caliber pistol, police said, adding that about a dozen other people were injured as they tried to escape from the school.

The gunman then shot himself in the head, and died hours later at a hospital.

Witnesses described a scene of mayhem in the leafy lakeside community, in which the assailant scoured the school for victims while shouting "Revolution!"

Today, grieving students placed candles outside the school, which was still encircled by police tape as forensic experts sought to reconstruct the shooting spree.

Today was declared a day of mourning in Finland and memorial services were planned across the country. In Tuusula, a town of 34,000 people, a church was turned into a crisis center with experts on hand to comfort grieving residents. Flags were flying at half staff across the nation.

Gun ownership is fairly common in Finland by European standards, but deadly shootings are rare. Finnish media reported that a school shooting in 1989 involved a 14-year-old boy who killed two other students apparently for teasing him.

Police chief Matti Tohkanen said Auvinen belonged to a gun club and got a license for the pistol on Oct. 19. He did not have a previous criminal record and "was from an ordinary family," Tohkanen said.

Students said the shooter often wore the same clothes to school — brown leather jacket, black trousers and checkered shirt — and usually carried a briefcase.

Tuomas Hulkkonen, another student, said he knew the gunman well, adding that the teen had been acting strange lately.

"He withdrew into his shell. I had noticed a change in him just recently, and I thought that perhaps he was a bit depressed, or something, but I couldn't imagine that in reality he would do anything like this," Hulkkonen told Finnish TV broadcaster MTV3.

More than 400 students aged 12 to 18 were enrolled at the school, officials said.