NEW YORK, August 28. /TASS/. Relatives of Paul Whelan, a US national detained in Russia on charges of espionage, claim that complaints to human rights organizations cause the detention facility staff to exacerbate the conditions of his detention, his brother David Whelan told TASS in a letter sent on Wednesday.

"Paul has complained publicly at his hearings as well as in letters to human rights groups," the letter states. "Even though it is his right to communicate to Russian human rights monitors, he has seen a noticeable drop in prison staff professionalism since he did so. Paul used an emergency notification system in the prison when he was injured and it took nearly an hour for a guard to respond."

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.