The Apple Watch has enjoyed a reputation as an excellent fitness companion thanks to its smart health features, which have even played a part in saving lives (more than once). However, medical tech firm Masimo claims that Apple stole patented technologies in order to make those features possible.As reported by Bloomberg, Masimo reportedly filed a lawsuit against the Cupertino-based tech firm for infringing ten patents owned by it and its spinoff, Cercacor Laboratories. The patents include important technology for “non-invasive monitoring” of the user’s pulse and other physiological signals. The lawsuit claims that these patents were used for the Apple Watch series 4 and series 5—in fact, Masimo says that Apple did so knowingly.

According to the firm, Apple contacted the company back in 2013 for a potential collaboration. But instead of developing a product together, Apple poached important employees, including Masimo’s former chief medical officer and and a former scientist, who both then worked on the Apple Watch’s health functions.

Masimo states that these former employees divulged confidential and sensitive information. The company is seeking compensation for Apple’s “willful and deliberate” patent infringement, as well as an injunction to block the further use of its technologies in Apple’s products.

This isn’t the first time the iPhone maker has been hit with lawsuits over unethical conduct concerning everything from its virtual assistant Siri to the lack of action to remedy serious design flaws.