At least six Russian soldiers have been held after the beating of a conscript, whose injuries were so severe his legs and genitals were amputated.
Bullying of conscripts is a widespread problem in the Russian army
The incident took place at the Chelyabinsk Tank Academy in the Ural Mountains over the New Year.
Eight other conscripts were also seriously injured.
Investigators say more senior soldiers carried out the beatings, with the co-operation of commanding officers.
Private Andrei Sychev contracted gangrene after he was forced to squat for several hours on New Year's Eve, then tied to chairs and beaten, according to the investigators.
Doctors treating the conscript say he is in a "stable" condition.
Russia's Defence Minister has ordered a military commission to look into the beatings.
Russia's Defence Minister Sergei Ivanov has ordered a public inquiry
Sergei Ivanov said the findings would be made public.
The authorities have been criticised by human rights groups who say the response to the incidents at the academy has been slow.
Media reports suggest the academy, which is situated about 1,900 km (1,180 miles) east of Moscow, may now be closed down.
Bullying in the armed forces is said to be widespread.