A second blast at the site of the terrorist attack on the Nevsky Express train was targeted at a group of investigators, the Investigative Committee at the Russian Prosecutor General's Office said on Tuesday.
Three cars of the Nevsky Express high-speed train from Moscow to St. Petersburg derailed Friday evening after an explosive device equivalent to 7 kg (15 lbs) of TNT detonated on the railroad tracks. A second, weaker bomb exploded on Saturday at 2:00 p.m. (11:00 GMT) at the site of the attack.
There were no injuries or casualties reported from the second blast.
According to the latest information, 26 people were killed and more than 90 injured when the train derailed. A criminal case into the Nevsky Express bombing was launched on charges of terrorism.
Forensic examination established that the second explosive device had a remote detonator, and was activated using a cell phone.
"It gives us grounds to believe that the second explosion near the site of the [first terrorist attack] could have been targeted directly at the investigative group," the committee said in a statement, adding similar tactics are often used by militants in the North Caucasus.
The cases on the two explosions have been consolidated into one.
"This case has been consolidated with the parent case on the Nevsky Express explosion, which occurred on November 27," the statement says.
A police source in the Tver Region told RIA Novosti that police found a house where at least four suspected terrorists had been hiding at the moment of the attack.
The investigative department said a jacket, which had letters from a prison inmate in the pockets, was found near the site of the crash.
Law enforcers have already compiled an identikit image of one suspect in the terrorist attack based on descriptions from eyewitnesses in nearby villages, who said the man was attempting to rent a house in the village "for his relatives."
Police in the neighboring Novgorod Region said they were looking for a 30-year-old man and a woman wearing a light-colored jacket, driving a Lada car.
It is still unclear whether Russian serviceman Pavel Kosolapov and militant leader Doku Umarov, wanted for the 2007 attack on the same train line, are related to the November 27 bombing.
MOSCOW, December 1 (RIA Novosti)