The US Department of Justice has begun a criminal investigation into the possible manipulation of bitcoin pricing.
Bloomberg reported that four anonymous sources had told it that the investigation is focused on forms of market manipulation such as spoofing – entering and later cancelling orders in an attempt to shift the valuation of an asset.
US prosecutors are said to be working with the Commodity Futures Trading Commission (CFTC) Con the investigation.
Bitcoin is 1.1% down on the day, trading around $7,520, after initially falling 3% to a six-week low on the back of the news. That follows a drop of nearly 48% since the beginning of the year.
In December last year the cryptocurrency peaked at $17,900. It near- halved that value in just 48 hours in January, before falling another 50% in February to below $7,000.
Regulators in the US and the UK have increased their focus on the cryptocurrency, with the FCA warning in April that crypto trading was a regulated activity and market abuse would lead to enforcement action.
Late last year the CFTC launched trading in bitcoin futures.