McDwyer was a Psi Corps telepath with Department Sigma who had trained at the Academy with Ysidra Tapia. In 2253 McDwyer was with the Department Sigma operation that took over the IPX excavation of a Shadow Vessel on Syria Planum, Mars. While attempting to determine if the ship was alive and/or sentient McDwyer touched the craft and was instantly driven insane, plagued by horrific visions of black insect-like things. McDwyer later escaped and leaving a trail of bodies in his wake, ended up at the abandoned hotel Tharsis where he was cornered and eventually killed by Psi Cop Alfred Bester who had arrived on site with McDwyer's former Academy classmate Tapia ahead of Sigma.