Lawyers who sued Facebook Inc. and Cambridge Analytica over alleged improper harvesting of users’ personal data say they fear evidence will disappear as the British data-mining company folds up part of its corporate web.

Cambridge Analytica and its SCL affiliates, which worked for the campaign that saw the election of President Donald Trump, have filed for court protection to liquidate in the U.S. and U.K. British employees were sent home recently, told no buyer had emerged to keep the company going.

Lawyers who sued in the name of millions of Facebook users say they haven’t been able to contact one of the shell companies that make up Cambridge Analytica’s corporate family, and have a “legitimate concern regarding the preservation of documents and other evidence.”

Cambridge Analytica Holdings LLC, a company created in Delaware in 2014, which appears to be a key element of the corporate family, didn’t file for bankruptcy anywhere, according to the plaintiff’s attorneys.

U.K. administrators handling the bankruptcy proceeding in the High Court of Justice, Business and Property Courts of England and Wales, didn’t respond to inquiries about the status of Cambridge Analytica Holdings.