Russian FSB Major General Sergei Sokolov, 59, has been found dead in Moscow.
His body was founded in his apartment in the north of the Russian capital, Moscow, the Mash Telegram channel said.
An FSB retiree's card and a military identity card indicating his KGB and FSB posts were found next to the body.
The man last contacted his relatives in early March, according to reports.
He earlier worked for the 10th department of the Soviet KGB which was engaged in countering smuggling and illegal currency exchange deals.