Dogs of War

One of the last holdouts from the Insurrection, the 61 Cygnus "Dogs of War" were a secessionist terrorist cell operating out of the Magog asteroid belt orbiting New Jerusalem. A major civilian shipping route, the Dogs had been a hindrance in the system since late 2499, their founding date, but suddenly and mysteriously stopped operating mid-way through 2534.
Just as the Eridanus Rebels were founded by a military turncoat, the Dogs of War were a splinter-cell founded after Operation: TREBUCHET by the remainder of the military deserters, led by Colonel Watts' right-hand-man, former Lieutenant Abel Arcane, now taking the title of "Commodore". Setting themselves up in a similar fashion in orbit near the prosperous spaceports of New Jerusalem, the Dogs of War picked off merchant shipping coming to and from the planet, making a profit on the black market and hoping to force the pro-UNSC government out of office. Indeed, public opinion was definitely against the government, as more and more ships were captured and stripped of usable items, and the famine of '22 did nothing to abate the discontent. In 2533, the Dogs of War became more ambitious, attacking a UNSC Red Cross/Crescent medical supply ship bringing aide to the colony, holding the crew hostage as neutral parties tried to negotiate for their release.
Soon afterward, the Dogs of War suddenly stopped operating. No armed raiding shuttles or yachts were sighted, and the practice of using a supposedly "crippled" freighter as bait was not encountered at all. Exactly what happened to them remains unclear - a single shuttle was found drifting in space, but its occupants were subsequently arrested by agents of the Office of Naval Intelligence and executed for treason.