MOSCOW (Sputnik) — Earlier in the day, media reports appeared claiming that Poteyev died.
"We have to wait for official confirmation of the cause of [Poteyev's] death…. I'm still inclined to think that his death was caused by constant stress which aggravates any illnesses [he may have had]," Kovalev, who is also a member of the lower house of the Russian parliament, told RIA Novosti.
"And all this could have spurred him on to betrayal. But this is only a hypothesis," Kovalev added.
According to Kovalev, it is also possible that the United States staged Poteyev's death as part of its Witness Protection Program.
Poteyev was convicted in absentia in Russia of disclosing the identities of a group of alleged Russian agents arrested and deported by US authorities in 2010. He was subsequently sentenced to 25 years in prison.