Russian federal authorities in Moscow have taken over the investigation into a stabbing rampage in the city of Surgut that left seven people injured and was claimed by the extremist Islamic State (IS) group.
The Investigative Committee, the Russian analogue of the U.S. FBI, said in an August 20 statement that its main investigative department would lead the probe into the attack a day earlier, citing the "wide public resonance" of the case.
The move was made on the order of Investigative Committee head Aleksandr Bastrykin, the statement said.
The knife-wielding man in Surgut, the center of Siberia's oil industry, stabbed seven people on the street before he was shot dead by police, investigators say.
The IS-affiliated Aamaq news agency claimed the assailant was one of its militants.
Russian investigators have not identified the suspect or classified the attack as an act of terrorism.
The murder case was initially opened by the Investigative Committee's regional branch in the Khanty-Mansi Autonomous Region, where Surgut is located.
Investigators had said that the suspect was born in 1994. But the Investigative Committee's August 20 statement cited "clarified information" that he was, in fact, born in 1998.
Investigators said previously that they were looking into whether the man suffered from "possible psychiatric disorders."
Khanty-Mansi Governor Natalya Komarova visited the injured in the hospital late on August 19 and said that one of the victims was fighting for his life.
The Investigative Committee said on August 20 that one of the stabbing victims remained in serious condition, while the others were stable.
Russia's NTV television published video footage of what it said was a police officer chasing the assailant through the streets of Surgut. The video shows the man attempting to flee and then falling after being shot by his pursuer.