The day before Elon Musk spoke at a celebration for Tesla’s futuristic Cybertruck pickup in November, a Florida man, Paul Overeem, was arrested near the company’s Austin, Texas, factory and accused by authorities of planning a “mass casualty event” there.

The incident later made headlines. What went less noticed is what happened at Tesla’s event, which went ahead at the Austin factory. Security had been alerted to Overeem’s threats and was fully activated, according to two people with knowledge of the arrangements and documents viewed by The New York Times.