The United States stood behind its assertion that U.S. personnel in Cuba were deliberately attacked and raised the possibility Tuesday that it was by a virus, as lawmakers and even the FBI challenged the government's initial theory of "sonic attacks."

Doctors treating the U.S. embassy victims of suspected attacks in Cuba have discovered brain abnormalities as they search for clues to explain hearing, vision, balance and memory damage, The Associated Press has learned.

In 2014, numbness spread through all four of Chris Allen's limbs within minutes of climbing into bed at the same Havana hotel where American government workers were later targeted. Convinced the incidents must be related, Allen joined a growing list of private U.S. citizens asking the same alarming but unanswerable question: Were we victims, too?