Detained gunman participated in Bydyonovsk seizure
The man, known both as Aleksey Sokolov and Igor Idobayev, had allegedly been in hiding from law enforcement agencies.
In June 1995, a group of up to 150 Chechen militants led by Shamil Basayev attacked a hospital in Budyonnovsk, taking around 1,500 people hostage, most of them were civilians. More than 130 people were killed and 400 injured.
If found guilty, the detainee could be sentenced to life-long imprisonment.