Four held in Helsinki blast probe
HELSINKI, Finland -- Four people, including a 17-year-old youth, are being questioned by police investigating a bomb blast which killed seven people in a Finnish shopping mall.
The four are being asked about an Internet chat room on bomb making, which was used by a 19-year-old chemistry student suspected of detonating the device outside a McDonald's restaurant in Vantaa.
The suspect has been identified as Petri Gerdt, who died in the explosion.
The National Bureau of Investigation (NBI) said the four detainees are not suspects in the bombing itself, but may have helped Gerdt build the device.
"Four are detained for discussing with (Gerdt) the preparation of explosives and the effects," NBI Deputy Chief Jari Liukku told Reuters.
One of the four, a 17-year-old student, is being held on a preliminary charge of "assisting in a grievous act of destruction," the NBI told The Associated Press.
NBI Detective Chief Superintendent Tero Haapala told the AP that the boy, from southern Finland, was a chief suspect in "providing information about how bombs are constructed."
Officials have several days to hold suspects before filing formal charges.
Haapla said the suspected bomber "acted on his own."
"There were no others with him at the mall. We still have no clear picture of his motive," Haapla said.
Police said they did not think the bombing was linked to terror groups.
"The motive is the big question mark, but we don't think it has an international connection or with international terrorism," NBI Inspector Rabbe von Hertzen told Reuters.
Police believe Gerdt used an Internet Web site called "Forum for home chemistry" to teach himself bomb-making and seized his computer, which they say holds information on how to build explosives.
Authorities have since shut down the site.
The site's moderator, reported to be one of the four detainees who called himself "Einstein," told national broadcaster Finnish YLE the site was not used to plan an attack, Reuters reported.
The homemade explosive, weighing up to 3 kg and packed with metal shards, went off on Friday evening in one of Finland's largest malls in the Helsinki suburb where Gerdt lived.
Tuesday was declared a day of mourning in the relatively crime-free country. Flags were flown at half-mast, and some official buildings were closed.
Police have not been able to pinpoint how the bomb was made but said the explosive cocktail contained ammonium nitrate, a fertiliser used in the 1995 Oklahoma City bombing that killed 168.
Surveillance cameras and witnesses saw Gerdt arriving alone at the mall 20 minutes before the bomb exploded, police said.
Gerdt used the alias RC in the Finnish chat room but gave no clear clues that he was planning a bomb attack.
"I have not taken part in any larger accidents, but once I dreamt that a police car drove to the site of the explosion, but luckily I was already floating to other places," RC wrote on the site.
RC also quoted lyrics from dead U.S. rapper Tupac Shakur, saying: "I ain't a killer but don't push me. Revenge is like the sweetest thing."
Fellow students described Gerdt as a polite introvert with few friends who enjoyed basketball and studied chemical engineering.
Police said he had no criminal record, political affiliations or any known alcohol or drug problems, the AP reported.