The practice, which is a violation of the company’s policy, is particularly strong in China, according to The Wall Street Journal.

Amazon said on Monday it was investigating suspected internal leaks of confidential information by its employees for bribes to remove fake reviews and other seller scams from its website.

Amazon employees are offering internal data and other classified information through intermediaries, to independent merchants selling their products on the site to help them boost sales in return for payments, the Wall Street Journal reported on Sunday, citing sources.

The practice, which is a violation of the company’s policy, is particularly strong in China, the report added, as the number of sellers there are soaring.

“We hold our employees to a high ethical standard and anyone in violation of our code faces discipline, including termination and potential legal and criminal penalties,” a company spokesperson told Reuters.

Brokers for Amazon employees in Shenzhen are offering internal sales metrics and reviewers’ email addresses, as well as a service to delete negative reviews and restore banned Amazon accounts in exchange for payments ranging from about $80 to more than $2,000, the WSJ report said.

The e-commerce giant is also investigating a number of cases involving employees, including some in the U.S., suspected of accepting these bribes, according to the Journal report.