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For budding novelists looking to stand out, the website PaidBookReviews.org offers a package of 100 book reviews on Amazon for the low price of $2,200.

The website was one of five sites Amazon sued Friday in Washington state court, part of the online retailer's year-long campaign to snuff out networks of fake reviews on its site.

The company has filed three separate lawsuits since last April, targeting more than 1,000 alleged fake reviewers. Several sites Amazon sued have already shut down, and an Amazon spokeswoman said Monday that the suits have helped the company obtain information to go after people not directly involved in the lawsuits, resulting in Amazon banning some sellers and reviewers.

"We will continue to pursue legal action against the root cause of reviews abuse -- the sellers and manufacturers who create the demand for fraudulent reviews," the spokeswoman said in a written statement, "as well as the ecosystem of individuals and organizations who supply fraudulent reviews."

Amazon has a big interest in making sure its millions of customers trust its 5-star reviews system, especially because these reviews let buyers know how good or crummy products are before making purchases online. While Amazon repeatedly says only a small fraction of its reviews are fakes and it uses controls to take many of them down, the company may still find itself in an unending battle of cracking down on paid reviews websites that crop up when old ones are shuttered.

Amazon last April filed its first lawsuit against fake reviewers, marking the first time it's taken legal action against the practice. Then in October, it filed another lawsuit targeting more than 1,000 registered sellers on the website Fiverr, which lets people sell odd jobs and services for $5 or more.

In Friday's suit, Amazon sued California resident Jane John-Nwankwo, who the company claims owns and runs PaidBookReviews.org, as well as New York resident Chris Embry, the alleged CEO of AmazonVerifiedReviews.com. Amazon also sued the operators of AmazonReviewStar.com, BuyAmazonReviews.info and ReviewConnections.com, but Amazon couldn't identify those sites' owners.

AmazonVerifiedReviews.com appeared to already be shuttered, but it is registered under Embry's name. He didn't respond to a call for comment. PaidBookReviews.org didn't immediately respond to an email for comment.

Amazon is suing for trademark infringement and other claims. It's requesting the sites stop using Amazon's trademark, stop offering Amazon reviews for sale and help Amazon find those engaged in fake reviews.

Here's a PaidBookReviews.org video describing its services: