From Halopedia, the Halo wiki
Sergeant Joseph M. Poteet (SecNet username: TRIGTECH) was a soldier in the UNSC. He serviced Warthogs on Reach.
Sometime after the Fall of Reach, the Office of Naval Intelligence launched an investigation of a SecNet message exchange between Poteet and SGT Alasdair R. Schicker to determine whether he had inadvertently leaked classified information, including the location of Reach, to the Covenant. The man receiving the information was dubbed "Yuma".