Nine Democratic senators have sought reply from Amazon CEO Jeff Bezos in light of the recent firings of critics from the company, CNBC reported. The company fired four employees who publicly criticised the labour practices of the company.

In a letter addressed to the world's richest man, the nine senators, Elizabeth Warren of Massachusetts, Bernie Sanders of Vermont, Cory Booker of New Jersey, Sherrod Brown of Ohio, Ed Markey of Massachusetts, Kamala Harris of California, Kirsten Gillibrand of New York and Tammy Baldwin of Wisconsin asked for more clarity on Amazon's policies "regarding grounds for employee discipline and termination."

The letter was first posted by NYT. The employees who were sacked, reportedly, called for greater safety protection for warehouse workers.

The letter posted by the senators' states, "To understand how the termination of employees that raised concerns about health and safety conditions did not constitute retaliation for whistleblowing, we are requesting information about Amazon's policies regarding grounds for employee discipline and termination."

One of the fired employees was Chris Smalls, a warehouse worker who organised a strike at its Staten Island, New York facility. According to Amazon, Smalls was fired because he violated social distancing rules and not for organising the strike, CNBC noted.

Amazon also fired a Minnesota employee, Bashir Mohammad who spoke about the treatment of employees who continued coming to work amidst the pandemic. According to Amazon though, it was a progressive disciplinary action for inappropriate language, behavior, and violating social distancing guidelines.

The other two employees Amazon fired were Emily Cunningham and Maren Costa, who has criticized Amazon's climate stance in the past and its treatment of warehouse workers during the pandemic. Amazon said it fired Costa and Cunningham for "repeatedly violating internal policies."

The senators in the letter expressed that Amazon's vague public statements regarding violations of 'internal policies didn't adequately explain the workers' firing.

They further asked Bezos to answer external communications that constitute a disciplinary action for Amazon employees. The letter also sought clarity on whether Amazon's discipline and termination policies are the same for warehouse workers, tech workers, and executives.

The letter also stated if Amazon keeps a record of which workers participate in walkouts, strikes, or other organizing activities, among other things.

The senators have given Bezos until May 20 for a reply.

Recently, a 50-year-old warehouse employee in Northeast Illinois died of coronavirus. The case marks the fourth known case in the US.