A convicted Russian neo-Nazi has been found dead in what appears to be a suicide inside his jail cell in the Urals region of western Siberia, prison authorities confirmed Wednesday.

Maxim Martsinkevich, who went by the nickname Tesak (Russian for machete), was serving a 10-year sentence for a violent attack on synthetic cannabinoids dealers. Martsinkevich, 36, had three prior convictions relating to extremism and inciting hatred.

Martsinkevich was found dead in a pre-trial detention center in the Chelyabinsk region, where he was due to be transferred to Moscow for questioning as part of a criminal case opened in 1999, Interfax reported.

Investigators have launched a preliminary inquiry into Martsinkevich’s apparent suicide.

Martsinkevich’s lawyer Ivan Sidorov told Interfax that his client had “no reason” to commit suicide and alleged that “someone may have helped him.”

The state-run RIA Novosti news agency cited regional human rights officials in saying that neither Martsinkevich nor his friends had any complaints prior to his death.

Conflicting reports said that Martsinkevich may have left a suicide note allegedly asking to give a private diary and a book on communism to his wife, according to the Meduza news website.

During his lifetime, Martsinkevich had gained notoriety for founding a group that organized vigilante attacks on gay men and alleged pedophiles.