Romania's Directorate for Investigating Organised Crime (DIICOT) told AFP today it had detained a 42-year-old man with the initials LML after searching his home in Arad, eastern Romania, yesterday.
The suspect has been charged with cybercrimes for "repeatedly and illegally accessing email accounts belonging to public persons in Romania with the aim of getting confidential data" and will be held for 29 days, prosecutors said.
The man named as Marcel Lazar Lehel by Romanian media has already been sentenced for cybercrimes in the past.
Guccifer hit the headlines last year after he allegedly hacked the accounts of the Bush family, posting pictures of paintings by former US president George W. Bush online.
In January, Guccifer reportedly told the US website The Smoking Gun that his other victims included "Downton Abbey" creator Julian Fellowes and US actor Steve Martin.
Romanian authorities have refused to comment on the man's alleged activities outside Romania but DIICOT said they were working with US authorities on the case.