Oleg Zhukovsky, who handled deals with major clients in the timber industry, was found dead on Thursday afternoon in the empty swimming pool of his luxury country house near Moscow.
He had been tied up and tortured, business daily Kommersant reported, citing investigators.
A 'suicide note' found in the house read: "I am tired of living. I ask you not to blame anyone." Handwriting experts are ascertaining exactly who penned the note.
The paper said that investigators had found evidence that the house, in the elite Lesnaya Opushka community in the Odintsovo District, to the west of the capital, had been broken into, and that a plastic bag had been put over Zhukovsky's head.
Zhukovsky was known to have heart trouble, and may have died while being tortured, investigators added. However, there were reported to have been no signs of violence being used against the banker.
A senior official at VTB said: "Zhukovsky's colleagues had not noticed any suicidal tendencies. The late banker had planned to proceed with his work in the bank."
Zhukovsky oversaw VTB's deals with major timber companies. Large parts of the country's timber industry are rumored to be controlled by criminal gangs, and the national budget loses hundreds of million of dollars a year from illegal logging, which is also believed to be a major cause of wildfires in the country.