The FBI and U.S. Army conducted a training exercise in Boston gone wrong when they mistakenly raided the wrong hotel room and detained an innocent guest. 

During a joint training exercise in Boston, FBI and U.S. Army special operations forces personnel mistakenly raided the wrong hotel room and handcuffed an innocent guest. The practice raid was meant to involve the mock capture of a role player, but the team entered the wrong room and interrogated an unsuspecting guest instead. The police were called to the scene, and it was confirmed that the event was a training exercise gone wrong. Although the identity of the individual detained has not been released, no injuries were reported. The incident has prompted the FBI and USASOC to review their training procedures. 

Source: https://www.thedrive.com/the-war-zone/botched-fbi-army-special-ops-training-raid-captures-unsuspecting-hotel-guest