Russian investigators say Chechen separatists are most likely responsible for the deadly terrorist attack on a passenger train north of Moscow last month, but they have not ruled out other suspects.
Chechen rebels claimed responsibility for the attack soon after the bombing of the high-speed Nevsky Express between Moscow and St. Petersburg. But so did an ultra-nationalist group, and Russian investigators say they are examining both claims.
A member of the ultranationalist "Combat 18" group said in a statement posted on his blog that the group's fighters organized the attack.
But security analyst Dmitri Trenin from the Carnegie Endowment for International Peace in Moscow says he agrees with authorities who believe Chechen separatists are responsible.
"There was a theory that ultranationalists may have a hand in that, but I find it less likely than the other people, terrorists with Caucasian connections, with connections from the Caucasus that is," Trenin said.
The train bombing killed 26 people and injured about 100 others. It was similar to an attack on the same train in 2007.
Back then, investigators concluded that a former military officer, Pavel Kosolapov, was responsible, and there are news reports tying him to the latest attack. He is connected with Chechen rebels and remains a fugitive.
The most recent Chechen claim of responsibility was posted on the Internet on behalf of separatist leader Doku Umarov. Reports say he heads a network of separatist cells across Russia's volatile and mainly Muslim North Caucasus region that are fighting to break free from Moscow's rule.
Russian officials say this bombing was the first deadly terrorist attack in Russia outside of the North Caucasus in five years. In the North Caucasus, attacks on officials and law enforcement officers are a regular occurrence.
During his annual question-and-answer session with the public in early December, Prime Minister Vladimir Putin said much has been done to contain terrorism in Russia, but he said the threat has not been eliminated. His critics say the way the government executes its policies in the region serves to fuel the terrorism in the Northern Caucasus.
"There's clearly a lack of professionalism on behalf of many police personnel and others in the region. There's this problem of clannish rivalry in the region, there's the problem of corruption, which does not start in the North Caucasus," Trenin said. "Basically it starts in Moscow and goes all the way to the North Caucasus."
Days after the attack, several thousand people came to this state-sanctioned anti-terrorism rally in Moscow.
And despite Prime Minister Putin's request that the Russian public and security services be more vigilant, for the people at this rally in Moscow, the threat of terrorism lives on.