A new lawsuit is claiming that top tech stock Apple (NASDAQ:AAPL) infringed patented technology to use in its Apple Watch. The suit was brought by Masimo (NASDAQ:MASI), in league with its spinoff company Cercacor, and covers 10 patents, according to numerous media reports published late Friday. It was filed in federal court in California.

Masimo, a medical diagnostic tech specialist, and Cercacor allege that Apple appropriated the work under the guise of a business collaboration.

Gavel and scales of justice on a desk.

Image source: Getty Images.

Apple contacted Masimo in 2013, the lawsuit alleges. Following that, a series of meetings were held, after which the tech giant hired away important employees at both Masimo and Cercacor. Two notables to depart were Masimo Chief Medical Officer Michael O'Reilly and Cercacor Chief Technology Officer Marcelo Lamego.

O'Reilly, according to his LinkedIn page, began his employment at Apple in July 2013. He is currently vice president of Apple's medical technology unit. Lamego's LinkedIn page says he was at Apple from January to July 2014, working on the Apple Watch. The first Apple Watch was launched in April 2015.

The disputed Masimo and Cercacor patents cover noninvasive technologies that use light to monitor aspects of a user's health. Health monitoring was a novel selling point of the Apple Watch when it was launched.

Masimo and Cercacor have asked the court to cease Apple's use of the disputed technologies in both the Apple Watch 4 and Apple Watch 5. They are also requesting damages, and the return of confidential and sensitive information.

Apple has not yet publicly commented on the lawsuit.