Following Tuesday's re-emergence of rumours that Gearbox is working on Halo 4, an internal e-mail from Gearbox's Director of Technology, Corrinne Yu, has seemingly revealed that she's leaving the studio to work on Microsoft's Halo team.

Yu has been leading the programming teams of Borderlands, Brother in Arms: Hell's Highway, and Aliens: Colonial Marines at Gearbox, and apparently said the following in an e-mail (which fell into the hands of Kotaku) to other Gearbox employees:

"I was offered and recruited to the position of Principle (Lead) Engine Architect of Halo Franchise Team at Microsoft. I accepted the offer to lead the team to build the engines and games for future Halo's on Xbox'es and PC's at Microsoft."

Her CV certainly puts her in a prime position for such a role, having previously worked as the Lead Programmer for 3D Realms' Prey Engine in the 1990s as well as a stint at ION Storm as its Director of Technology.

It's by no means confirmation that Gearbox is working on Halo 4 although Yu does say that she "will continue to help Gearbox" in the e-mail, which suggests that there may be a working relationship between the two companies.