The Senate is holding a hearing Tuesday on the mysterious "sonic attacks" that reportedly sickened U.S. diplomats and other personnel in Cuba.
The U.S. State Department previously said U.S. government employees in Cuba began complaining about "physical symptoms" back in 2016. Those symptoms included hearing loss, dizziness and cognitive issues.
In late September 2017, the U.S. ordered most of its own personnel out of Havana. At that point, more than 20 officials had gotten sick.
The State Department has yet to say what kind of device caused the attacks or who the perpetrator was, but the Cuban government has denied involvement in the incidents.
Sen. Marco Rubio is leading Tuesday's hearing, which is supposed to establish the facts surrounding the attacks and look into how the State Department handled the incidents. The hearing was originally scheduled for last November, but it was postponed without a reason given.