One man died and five other people were injured when gunfire erupted last night at ZombiCon, a street festival attended by as many as 20,000 partiers in downtown Fort Myers, Florida, CNN reported. Festgoers “cleared out fast and cop cars and ambulances came,” according to Savannah Holden, who witnessed the mayhem from a hotel balcony. Police said four people were hospitalized with non-life-threatening injuries.

Zombies and undead-themed events have become increasingly big business as movies such as World War Z and TV shows The Walking Dead draw enormous audiences and dedicated fan followings. The Fort Myers event draws up to 20,000 people annually and feature bands, DJs, zombie themed exhibits and hoards of costumed revelers.

Pushing Daisies, the local artists charity that sponsors the event said they were “deeply saddened by the news of what happened within the footprint of our event.” The dead man was identified as Expavious Tyrell Taylor, 20, of Okeechobee, Florida. His aunt told CNN he was a college student in Miami.

Police have been asking festival-goers who might have captured images of the assailant while taking pictures and movies with their cell phones to share the evidence with authorities.