Amazon fired an employee for handing over customer email addresses to a third party seller on the site, the company confirmed on Monday.
The e-commerce giant said on Friday it had notified affected customers, adding that the seller had been blocked from Amazon.
"The individual responsible for this incident has been terminated from their position, and we are supporting law enforcement in their prosecution," an Amazon spokesperson wrote in an email to ABC News.
(MORE: Amazon investigating allegations workers were paid for confidential data, deleting bad reviews).
The company did not provide any details on the fired employee or third party seller.
The Wall Street Journal reported last month that Amazon was investigating leaks of customer data by employees in exchange for bribes from third party sellers. Amazon would not comment on whether this employee's behavior was part of that investigation.
(MORE: Amazon unveils smart microwave and new Fire TV Recast)Problems with third party sellers and a culture of fake reviews have been a growing problem for Amazon as it grows exponentially. The cottage industry of fake reviews has in turn spawned an industry that monitors fake reviews.