Russia’s FSB security service has asked a court to keep a Canadian-born former U.S. marine, who’s accused of espionage, in pretrial detention for another three months, the Interfax news agency reported on Tuesday.

Paul Whelan, who holds Canadian, U.S., British and Irish passports, was detained in a Moscow hotel room on Dec. 28 and is disputing the espionage charge, which could land him in prison for up to 20 years.

Whelan was due to be kept in pretrial detention until May 28 while investigators continue to look into his case. The FSB said it now wants him to be detained until the end of August, according to Interfax.

In February, a Russian court had extended his pretrial detention by three months. Whelan appeared in court in a cage on Feb. 22 and looked downcast when he spoke briefly to reporters before masked security officials cut him off.

“I could do with care packages, food, things like that, letters from home,” Whelan said.