Medical technology company Masimo accused Apple of infringing on ten of its patents in Apple Watch, as it launched legal proceedings seeking a ban on the sale of certain devices, Bloomberg reported.

Apple was accused in a lawsuit of stealing trade secrets and improperly using technology from Masimo and its spin-off Cercacor related to health monitoring, which the iPhone maker apparently obtained under the guise of a working relationship.

Masimo and Cercacor are seeking a ban on the use of their patented technology in the Apple Watch 4 and Apple Watch 5, along with damages and the return of confidential information.

The lawsuit detailed meetings between Apple and Masimo in 2013, which were held to discuss a potential collaboration. However, Apple went on to hire some of the company’s key employees, including chief medical officer Michael O’Reilly, who went on to become VP of Apple’s health technology efforts.

Apple then hired Ceracor’s CTO, Marcelo Lamego, both of which had access to sensitive technical information.

The US device maker was accused of stealing technology covering non-invasive monitoring using light developed by Masimo, to overcome performance issues of the Apple Watch. Apple also allegedly infringed on Masimo patents related to measuring oxygen levels in blood and heart rate using light emitters and detectors.

Last month, Apple was accused of infringing on patented technology developed by a cardiologist, who is seeking royalties on an Apple Watch feature which provides users with notifications of an irregular heartbeat.