(Reuters) -Apple ( AAPL ) was hit with a lawsuit in California federal court by a pair of neuroscientists who say that the tech company misused thousands of copyrighted books to train its Apple Intelligence artificial intelligence model.

Susana Martinez-Conde and Stephen Macknik, professors at SUNY Downstate Health Sciences University in Brooklyn, New York, told the court in a proposed class action on Thursday that Apple ( AAPL ) used illegal "shadow libraries" of pirated books to train Apple Intelligence.

A separate group of authors sued Apple ( AAPL ) last month for allegedly misusing their work in AI training.

TECH COMPANIES FACING LAWSUITS

The lawsuit is one of many high-stakes cases brought by copyright owners such as authors, news outlets, and music labels against tech companies, including OpenAI, Microsoft ( MSFT ), and Meta Platforms ( META ), over the unauthorized use of their work in AI training. Anthropic agreed to pay $1.5 billion to settle a lawsuit from another group of authors over the training of its AI-powered chatbot Claude in August.

Spokespeople for Apple ( AAPL ) and Martinez-Conde, Macknik, and their attorney did not immediately respond to requests for comment on the new complaint on Friday.

Apple Intelligence is a suite of AI-powered features integrated into iOS devices, including the iPhone and iPad. 

"The day after Apple ( AAPL ) officially introduced Apple Intelligence, the company gained more than $200 billion in value: 'the single most lucrative day in the history of the company,'" the lawsuit said.

According to the complaint, Apple ( AAPL ) utilized datasets comprising thousands of pirated books as well as other copyright-infringing materials scraped from the internet to train its AI system.

The lawsuit said that the pirated books included Martinez-Conde and Macknik's "Champions of Illusion: The Science Behind Mind-Boggling Images and Mystifying Brain Puzzles" and "Sleights of Mind: What the Neuroscience of Magic Reveals About Our Everyday Deceptions."

The professors requested an unspecified amount of monetary damages and an order for Apple ( AAPL ) to stop misusing their copyrighted work.