Fleet Captain Sidney Riley, a Terran/Deltan, was the commanding officer of the USS Tiger-A.
Riley began her career as a medical officer on the USS Wallace. When the Wallace was decommissioned, she was transferred to the USS Independence where she was promoted to Chief Medical Officer. Upon the promotion of Captain Idril Mar and the commissioning of the USS Ronin, Sidney was promoted to First Officer of the USS Independence-A under the command of Rear Admiral Jessa Kyrn Anassasi.
On Stardate 238505.04, Commander Sidney Riley was given command of the USS Tiger, a Steamrunner-Wolverine class vessel, which was given a semi-permanent assignment as a support vessel for Deep Space 17 in the Ithassa Region. On Stardate 238612.14, the Tiger was ordered to return to her home port, Starbase 118 Operations, as the primary support vessel for the station. Captain Riley and the crew of the USS Tiger were reassigned to Starbase 118 Ops at that time.
She was dispatched once again to the USS Independence-A when its commanding officer Commander David Cody disappeared out of the Ready Room on Stardate 238703.15, later verified as removed by the Greeters of the Odessey Waystation. With the supposed destruction of the Independence-A in the Mirror Universe on StarDate 238811.13, the crew returned to Deep Space 17 without a ship.
On StarDate 238811.16 Riley was posted as commanding officer of the USS Tiger-A, a Prometheus class vessel assigned to the Ithassa Region. Riley would continue to serve as the Tiger's commanding officer until her resignation on stardate 239103.14.
She also owned a cat, Andy.