MOSCOW, August 30. /TASS/. An investigation into the case of US citizen Paul Whelan, suspected of espionage in Russia, is de-facto over as the final indictment had already been filed, his lawyer Olga Karlova told TASS on Friday.

"The pretrial investigation will be officially declared over next week, but investigative measures are de-facto over. The final version of his indictment has been filed, under Article 276 (espionage), as was the case from the very beginning," she said.

Karlova refused to comment on the nature of Whelan's charges, saying that she had signed a non-disclosure statement.

US citizen Paul Whelan, 48, who also holds British, Canadian and Irish passports, is a global security chief at BorgWarner, a Michigan-based automotive components company. The Russian Federal Security Service (FSB) informed that Whelan had been detained on December 28, 2018 in Moscow while on an alleged spy mission. A criminal investigation was opened against him on espionage charges carrying a punishment of up to 20 years behind bars.