'X' logo installed atop Twitter building, spurring San Francisco to investigate permit violation

 SAN FRANCISCO (AP) — The city of San Francisco has opened a complaint and launched an investigation into a giant “X” sign that was installed Friday on top of the downtown building formerly known as Twitter headquarters as owner Elon Musk continues his rebrand of the social media platform. 

The X appeared after San Francisco police stopped workers on Monday from removing the brand's iconic bird and logo from the side of the building, saying they hadn't taped off the sidewalk to keep pedestrians safe if anything fell. 

Any replacement letters or symbols would require a permit to ensure “consistency with the historic nature of the building” and to make sure additions are safely attached to the sign, Patrick Hannan, spokesperson for the Department of Building Inspection said earlier this week. 

Erecting a sign on top of a building also requires a permit, Hannan said Friday.