A Russian soldier has been detained following an attack at a military base that left three soldiers dead, officials say.
An officer was killed with an axe before two soldiers were fatally shot near the southern city of Voronezh.
The suspect, named as Pte Anton Makarov, was based at the Baltimor airbase, investigators say.
He allegedly seized the officer's pistol which he used to kill the other soldiers in Monday's attack.
A fourth soldier was shot and wounded.
Earlier, the RIA Novosti news agency reported that hundreds of Omon and Sobr special forces soldiers were hunting for the fugitive. Voronezh is about 465km (290 miles) south of Moscow.
But he has since been detained and officials said the soldier was being interrogated.
It is not yet clear why the soldier attacked the officer and opened fire.
One unidentified source told the Interfax news agency that the shooting started when an altercation broke out during an inspection, but this account has been denied by military officials.
Meanwhile, rights activists claimed Pte Makarov had been a victim of hazing. Hazing usually refers to induction rituals that can include physical violence or degrading and dangerous pranks.
Vladimir Osechkin, who founded the anti-torture project Gulagu.net, told the AFP news agency that the soldier had been beaten by his superiors.
Russia's army insists hazing and bullying have been clamped down on in recent years.