Kelly is a minor character in Syphon Filter 3. He appears in Teresa Lipan's flashback during her time as an ATF agent in the early 1990s. In that time, Kelly was an ATF Special Agent, who worked alongside other ATF agents including Teresa Lipan and DeMarco. Kelly and the ATF were sent to investigate the FBI discovery of a survivalist militia compound and a satellite impact site near Paradise in northwestern Montana. When Teresa Lipan planted homing beacon devices on the powerlines, she asked an ATF strike team to be sent to the militia compound, which included Special Agent Kelly. Unfortunately for the ATF agents, they were caught in a conspiracy between the NSA, who sought to retrieve a top-secret data from the crashed satellite, and the survivalist militia, who now possessed the data. The NSA were determined to get their hands on the data by killing anyone in their way, including other federal agents like the ATF.
When he reaches the militia compound, Kelly was found and captured by two militia members, who beat him up a bit and then tied him under the stairs of a warehouse right by a well. He later radios Teresa about his situation and asks her to rescue him. Teresa assures him that she will do so. He was later found and rescued by Teresa. Shortly after, both ATF agents eliminated several NSA agents. After the gunfight, Kelly tries to persuade Teresa to abandon the operation and get out of there but Teresa wanted to stay behind and rescue the Oakton family first. He was also asked to not get involved in this (conspiracy). Kelly complies and leaves the compound.
His whereabouts are unknown but it is presumed that he is still alive.
He only appears in the level Militia Compound in Syphon Filter 3. In-game, he appears identical to ATF agent DeMarco, complete with the standard ATF uniform.