DISCLAIMER: Harry Potter belongs to JK Rowling. I'm just playing in her world. Any mentions of actual persons, living or dead, is done in a purely fictional context.
Tom Riddle, aka Lord Voldemort, was nervous. He just noticed the tail on him, and while under normal circumstances he would have AKed them when there were no witnesses around, he also noticed that his tail consisted of at least two Yanks. At least two because that's the number he noticed. There were probably more. American technomages from the CIA's MK-ULTRA department were one of the few things that scared Riddle, more so than Bumblebore.
Back when Riddle was first working on the whole dark lord thing, he sent an agent into America to "test the waters". After arriving in Salem Massachusetts, that agent vanished. The next two agents he sent looking for the first found him working as a janitor at a McDonalds in Southie with his magic stripped and memory erased. When they followed him, they were led to a bar in Boston frequented by magical members of Sinn Féin where they proceeded to have the crap beat out of them, their skin dyed Kelly Green, and their wands snapped. They were later found at the front door of the British Consulate in Cambridge where they were recognized as Death Eaters and sent to Azkaban. Meanwhile, the British Ministry of Magic received a terse message from the American Department of Magical and Paranormal Affairs telling the Brits to keep their trash on their side of the ocean. After that, Riddle decided to give the Americans a wide berth.
Capt. Curtis Saxon, US Army Magical Intelligence Command (MAGICOM), currently attached to CIA MK-ULTRA, looked at Riddle through his AN/PVS-666 Mage Vision Goggles (MVG) and frowned. Designed to look like a pair of muggle sunglasses, the AN/PVS-666 MVG was standard issue for all MAGICOM forces. All magic users can be identified by their distinctive aura, visible to an MVG wearer. Skilled MVG operators can also identify the classification of an individuals magic, and any adjuncts attached to them such as a wand or ward. What Capt. Saxon saw looking at Riddle were several black threads stretching away from him and off in different directions. Maj. Mike Aquinas, Saxon's team leader, saw him frown and trained his MVGs on Riddle. "He's got Horcruxes." Aquinas said. "Looks like six of them."
Horcruxes were used by dark wizards as a means of life insurance, and required an act of murder to create. Saxon and Aquinas looked at Riddle with utter revulsion. Saxon spoke next, "Want me to have an MSM team trace them down?" he asked. MSMs were Magical Support Teams, capable of tracing down magical treads to their origin, and then sending an Electro-Magical Pulse weapon at it. EMPs could disrupt a persons magical signature and "cleanse" an item by wiping magical energy off it. A powerful enough EMP could also permanently wipe a persons magic if they are too close to it when it goes off. Such a pulse is often fatal as in addition to losing their magic the person gets a lethal dose of radiation.
The Major thought a while. "Tempting with this piece of shit, but the Limey Ministry wouldn't appreciate the favor." he finally said. This M-Team was under the control of MK-ULTRA, and while the NCA might go toe-to-toe with the Brits since Riddle had already tried to bring Death Eaters into the US (They were dealt with in a very funny manner by Irish FBMI agents in Boston.), their mission at present was to observe. "Make a signature recording, and we'll up channel it. We'll let the DMPA notify the Brits." Their mission complete, the M-Team blended into the woodwork like the professional hunters of men that they were.
Riddle noticed his tail was gone. This scared him even more because he didn't see where they went.