As Amazon moves ahead with its annual Prime Day sale, the company is still facing criticism for selling hateful merchandise on its platform, and is now facing scrutiny from a prominent lawmaker.

Earlier this month, a report published by two advocacy groups found numerous examples of white supremacist and neo-Nazi merchandise available on Amazon, from a burning cross baby onesie to a neo-Nazi Pepe the Frog fidget spinner. The report also noted that several white supremacist writers’ works were available on Kindle. The company removed the offending material, but it was only the latest example of a criticism the company has faced for years.

Amazon has faced similar criticism for years

But Rep. Keith Ellison (D-MN) has some questions for the company. In a letter provided to The Verge and sent today to CEO Jeff Bezos, the lawmaker says “there appear to be a disturbing number of groups with hateful, racist, and violent agendas making money using Amazon’s platform.”

“Historically, Amazon has not responded effectively to this issue,” Ellison writes, “and continues to allow hate groups and SPLC-identified neo-Nazis and white nationalist writers to make money using its platform.”

The letter raises several questions for the company. Among them: How much money has Amazon made from the sale of hateful material? How does Amazon enforce its policies? And can it commit to stop publishing hate groups’ material within three months?

“Third party sellers who use our Marketplace service must follow our guidelines and those who don’t are subject to swift action including potential removal of their account,” an Amazon spokesperson said in a statement.

Ellison is requesting answers to the questions by July 31st.