Explosion at California Cheesecake Factory leaves questions

(CNN)A man tossed an explosive device into a Pasadena Cheesecake Factory on Thursday evening, scattering terrified diners and sparking an police search for the perpetrator.

Although no one was injured, the device filled the restaurant with heavy smoke and set off panic and confusion, according to witnesses who spoke with CNN affiliate KABC.
Witnesses said the man ran away after throwing the device.
Pasadena police described the explosive as a "homemade pyrotechnic device" and said the man was described by witnesses as a "male of Hispanic or Middle Eastern descent ... with a heavy beard and wearing all black clothing and a black beanie."
    Officials said federal authorities have been notified "out of an abundance of caution."