Philadelphia police said detectives were investigating the possibility that a bullet struck a window at the Comcast Technology Center on Thursday.
No injuries were reported, police said.
The incident was reported shortly before 2:30 p.m. at the 60-floor skyscraper at 1800 Arch St., police said.
Cracks were visible from the outside on what was reported to be a 23rd-floor window.
Police said Comcast employees reported that the window shattered and there was a small hole visible. Detectives investigating the scene could not find any obvious damage inside the building from a projectile, police said.
The police Crime Scene Unit was expected to investigate.
John Demming, senior vice president of corporate and financial communications for Comcast, said in an emailed statement: “A window was shattered on an upper-level floor of the Comcast Technology Center this afternoon. The safety of our employees is our top priority and thankfully nobody was injured. Our security team is working closely with local authorities on the investigation of the cause.”