Bestselling Brazilian romance novelist Cristiane Serruya has pulled one of her novels from sale after she was accused of plagiarising some of the biggest authors in the genre.

American author Courtney Milan, whose books are regulars on the New York Times and USA Today bestseller charts, said she was first alerted to the alleged plagiarism by a reader. A law professor turned historical romance author, Milan alleges that Serruya’s novel Royal Love “copied, word-for-word, multiple passages from my book The Duchess War”, laying out a range of instances on her blog.

“I have not listed all of the similarities because, quite frankly, it is stomach-churning to read what someone else has done to butcher a story that I wrote with my whole heart … I wrote The Duchess War in the midst of a massive depressive spell and I bled for every word that I put on the page,” wrote Milan. “But you know what? Cristiane Serruya has to be the biggest idiot out there. I’ve sold several hundred thousand copies of this book. I’ve given away several hundred thousand copies on top of that. Does she think that readers are never going to notice her blatant plagiarism?”

One line from Milan’s novel reads: “Her nostrils flared; he almost thought she might stamp her foot and paw the ground, like an angry bull.” Serruya’s Royal Love contains this line: “Her nostrils flared; he almost thought she might stamp her foot and paw the ground, like the bull that had attacked Siobhan.”

“‘If you’re any good in bed, I might fall in love with you. If that is going to be anathema …’ ‘No,’ he said swiftly. He looked away from her, and when he spoke again, there was a slight rasp to his words. ‘No. That would be perfectly … unobjectionable,’” runs an interchange between Milan’s protagonists.

A scene in Serruya’s novel reads: “She stared back, both fascinated and appalled. ‘And if I fall in love with you? Is it going to be anathema?’ ‘No,’ he said swiftly, and looked away from her. There was a slight rasp to his words, when he faced her again. ‘No. That would be perfectly … unobjectionable.’”

After Milan posted on her blog, fans and fellow authors shared further instances of Serruya’s alleged plagiarism of authors including Bella Andre, Tessa Dare, Loretta Chase and Lynne Graham in her novels Royal Love and Royal Affair, corralling their findings under the Twitter hashtag #CopyPasteCris.

Responding on her now deleted Twitter account, Serruya initially expressed surprise at the accusations, and then blamed the overlap on a ghostwriter she said she had hired from freelance services marketplace Fiverr. The Guardian has contacted Serruya for comment.

“Wow, wow, wow. I just wake up to this. How could I have been plagiarizing 5 authors? I love your books, @TessaDare and I am a lawyer. I’d never do such a thing,” she wrote. “I just woke up to distressing news that my work has plagiarism from other authors. I am taking down all the works I did with a ghostwriter on Fiverr – who btw has closed the account – until I have made certain this is solved.”

On Wednesday, Serruya’s novel Royal Love was pulled from sale online, and withdrawn from the Rita competition for romance novels run by Romance Writers of America, which released a statement announcing it had “removed the entry from the contest and [is] investigating the matter further.”