In early 2258 Jack took part in the investigation of Frank Benson's murder. Unbeknownst to Garibaldi, however, Jack gave support from inside the station to help Knight One undetectably dispose of Benson's body.
On New Year's Eve of 2258, Jack quietly assisted a man named Devereaux in setting up and shipping out some jamming equipment designed to prevent any signals from reaching Earthforce One as it approached the transfer station on Io (the plan ultimately involving the destruction of the ship and the death of President Luis Santiago). Garibaldi discovers the plot when he discovers the jamming devices. Jack shoots him in the back before he could warn anyone, taking his link and leaving him for dead. Garibaldi does not die, however, and is rushed to Medlab. After hours of surgeries, his situation becomes stuck at critical but stable. Commander Sinclair orders Jack to keep a guard posted over the Chief at all times and also order him to find Devereaux and his two companions. Jack murders all three men, making it look as though he fired on them in self-defense.
After over three weeks of being in a coma, Garibaldi finally awakens. At first he cannot remember who shot him, relieving Jack. However, soon thereafter Talia Winters scans Garibaldi and uncovers that the aide was the one responsible for the shooting. Jack is arrested by Lou Welch and other members of security. Garibaldi interrogates him personally. Jack cannot help but gloat about being on the winning side of a "new order" that is about to take over on Earth. He gives Garibaldi a strange salute and says "Be seeing you" at the close of the interrogation (the same farewell Psi Cop Bester gave Sinclair the previous year.) President Morgan Clark personally orders Jack sent back to Earth, ostensibly for a deeper investigation. However, en route Jack is transferred to another ship and disappears. It is unknown what happens to him afterwards.