Amazon (AMZN, Financials) is the e-commerce and cloud computing giant now under scrutiny by the U.S. Senate for suspicions that Chinese influence had a role in decisions made about its online marketplace.

A source citing people involved in the inquiry said Republican aides on the Senate Small Business Committee said they uncovered evidence of potential negligence related to China-based activities.

The investigation comes after reports that Amazon employees in China were allegedly selling favors to merchants who wanted to get better treatment on the platform.

One inventor told committee researchers that an intermediary promised to leverage connections with Amazon workers in China to assist fix marketplace problems in exchange for money.

The allegations challenge Amazon's control of third-party merchants, which constitute around 60% of the products sold on the platform.

Some shops have complained for years about unexpected suspensions, inconsistent enforcement and difficulty appealing penalties. Those challenges produced the need for middlemen who say they have access to internal decision-making.

The probe comes on top of wider regulatory challenges facing Amazon, including antitrust claims and allegations of deceptive business practices. The corporation has denied any misconduct in those cases.

Now investors will watch to see if the Senate committee would seek testimony, documents or policy changes from Amazon.