The U.S. military inquiry into the so-called Havana syndrome, the mysterious illness claimed by a litany of American intelligence officers, is tapping a controversial contractor: a private surveillance firm that once boasted of its ability to stalk American intelligence officers. Documents obtained by The Intercept through a Freedom of Information Act request reveal that technology from the Virginia-based startup Anomaly 6 has been used to assist the “Anomalous Health Incidents Cross Functional Team,” the Pentagon’s official Havana syndrome investigatory task force. That group studies a cluster of strange symptoms claimed by personnel from U.S. spy agencies, the State Department, and…