Update: San Francisco police told Polygon that officers responded to Unity’s San Francisco office “regarding a threats incident.” A “reporting party” told police that “an employee made a threat towards his employer using social media.” The employee that made the threat works in an office outside of California, according to the police statement.
I was thinking exactly the same, and the reason was “alleged threats”.
And apparently you were right, as reported by Polygon (https://archive.ph/KcdoZ)