THESSALONIKI, Greece (AP) — Greek police say a cellphone seized from a Russian man the U.S. wants extradited for allegedly laundering vast sums through bitcoin transactions should provide key data for the investigation.

The U.S. Department of Justice has identified the suspect as Alexander Vinnik, 37. It says he allegedly laundered more than $4 billion through BTC-e, one of the world's largest digital currency exchanges — which he allegedly operated.

He was arrested Tuesday while on holiday with his family in northern Greece and detained pending the extradition process.

Thessaloniki security police chief Avraam Aivazidis told The Associated Press on Thursday that arresting officers grabbed the suspect's cellphone before he could lock it, ensuring vital data were not lost.

The suspect denies wrongdoing, and said he will fight extradition to the U.S.