Surveillance video released by the Philadelphia Police Department shows an extremely calm gunman fire an assault rifle in broad daylight while crossing a busy street, and walk away as if nothing happened. 

The incident happened on the 3000 block of Cumberland Street in the city's Strawberry Mansion section on July 31.

The video shows the man walking down a street with the rifle held slightly behind his back. As he crosses the street, the gun appears to fire into the ground. The discharge appears to be accidental. 

The man turns to look at the ground -- he jumps a little bit but a lot less than one would expect.  The images aren't totally clear, but he appears to be checking his phone as he walks away. 

It's unclear what the man was doing with the gun. A police spokeswoman said police do not know at this time if it was used in the commission of a crime, if the gunman was looking for someone. 

Anyone with information is asked to call Philadelphia Police.