A graphic video posted by police on Tuesday showed the elderly woman leaving Peter Piper Pizza in Tucson just after 3:45 p.m. When she exited the establishment, the man flung the door open -- blocking her path for a brief moment -- before striking her with the weapon. He was captured on video running away with a pizza in one hand and the pipe in the other.
The woman was seen holding her head after the encounter, although Tucson's KOLD-TV reported that she didn't go to the hospital.
The suspect was described as a Hispanic male, 5 feet 6 inches or shorter, with a "wrinkly face," police said.
"Investigators are asking if anyone witnessed the robbery, or a male fleeing the area with a pizza box, to please call 911. If you wish to remain anonymous, you can call 88-CRIME," the Tucson Police Department wrote on Facebook.
The department added: "Please call so we can get this guy off the streets."