Google has agreed to improve its ability to retrieve data requested by enforcement agencies, in a settlement with the U.S. Department of Justice of a case in which Google was accused of losing data critical to the investigation of a $4 billion cryptocurrency money laundering scheme.

As part of the settlement, Google avoided penalties, but said it has spent over $90 million to improve its ability to respond to future data requests.

An independent professional will evaluate Google's compliance with the terms of the settlement.

Federal prosecutors said Google had failed to provide requested data stored outside of the U.S., halting execution of a 2016 search warrant related to the investigation of the criminal cryptocurrency exchange known as BTC-e.

BTC-e was charged in 2017 for an alleged $4 billion dollars worth of money laundering and other crimes. Its operator, Alexander Vinnik, was extradited from Greece to the U.S. in August to face a 21-count indictment.

“The warrant underlying this agreement was sought in connection with a significant criminal investigation,” said U.S. Attorney Stephanie Hinds of the Northern District of California.

The warrant was served under the Stored Communications Act, which requires providers like Google to turn over “complete and prompt” responses to legal inquiries. The warrant was determined to have probable cause and had been signed by a judge.

Federal prosecutors said that Google took steps to prevent the data from being repatriated from Greece.

The government litigated with Google for two years about the issue, culminating in Congress clarifying that the Stored Communications Act does in fact relate to data stored overseas. During the legal dispute, the Department of Justice said data targeted by the search warrant had been lost by Google.