The FBI is investigating a report filed by an unnamed Bitfinex user alleging that funds were stolen from their account, CoinDesk has learned.

According to an incident report filed on 14th September, a Cambridge, Massachusetts, resident stated that they lost $1.3m in bitcoin tied to the hack and subsequent $70m theft from Bitfinex.

The Cambridge Police told CoinDesk that the matter had been referred to the FBI after an initial investigation. Bitfinex representatives have previously said that they are working with the FBI as part of its investigation into the hack.

The incident report – and word that the FBI is looking into the matter – offers a rare detail into the post-hack investigation said to be taking place. However, the status of the investigation and the extent to which the FBI has pursued the lead remains unknown at this time.

The resident said that they learned that $1.3m had been stolen from their Bitfinex account. According to the document, the user had $3.4m in total personal holdings.

It was further reported that the loss incurred was reduced to $720,000 when factoring in IOU tokens issued by Bitfinex after the exchange initiated its recovery efforts.

The document does contain one other idiosyncrasy. The reporting officer noted that the amount translated to "70,000,000 in bitcoin", which roughly corresponds to the amount, in dollars, lost during the hack.

The Bitfinex hack rocked the bitcoin world when it occurred in early August, resulting in the loss of nearly 120,000 bitcoins. The incident impacted bitcoin markets during the month that followed, though prices have since recovered.

H/t Brian Cohen, MrFelt

The text of this report has been updated for clarity.

Image Credit: Arnaldo Jr / Shutterstock.com