The FBI used a mole to secretly record employees at AmTrust Financial Services  (AFSI) , a whistleblower told the Wall Street Journal Tuesday. AmTrust shares were down nearly 20% in Tuesday afternoon trading. 

Shares were trading at more than seven times their normal volume.

An auditor at the accounting firm BDO USA LLP used a listening device disguised as a Starbucks gift card to secretly record conversations with employees at the insurer. 

The recordings from 2014 were part of a federal investigation being led by the Securities and Exchange Commission into the company's accounting practices. 

Amway has grown into the country's third largest insurer for workman's comp claims over the past 19 years. It had revenue of $5.45 billion in 2016. 

Editor's note: Story has been updated since 11:52 am EST.

(What will move markets this quarter and how should investors position themselves ahead of time? Jim Cramer sat down with four of TheStreet's top columnists recently to get their views. Click here to listen to his latest Trading Strategies roundtable with them and read their advice for stocks, bonds, forex and gold.)

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