HOUSTON - Police say they have found a 9mm casing after word of gunfire spread quickly through the Houston Livestock Show & Rodeo Wednesday night.

During a press conference Thursday, police said that 17-year-old Raymond Colbert has been arrested on an evading arrest charge. Police say that Colbert matched the description of someone who possibly fired a shot. When the officers approached, he reportedly ran away.

Police added that although a spent casing was collected, a firearm has not been found. The casing was found in the northwest corner of the carnival, near the Westridge gate.

Police swarmed as witnesses reported hearing gunshots near the carnival shortly before 10 p.m.

Right now, every guest has to go through a metal detector and security guards are supposed to be looking for weapons in purses and bags. RodeoHouston says it is evaluating possible security changes.

"I would say that are current security protocol is sufficient, it is of great concern for us that a spent shell was found on our grounds we will assess the situation and make any necessary adjustments," said Joel Cowley with the Houston Livestock Show and Rodeo.

The chaos that followed reports of gunfire was filled with conflicting witness statements on social media, even as RodeoHouston's official Twitter account kept the public up to date.

At 10:03 p.m. the rodeo tweeted, "We are monitoring the situation on the grounds. More information will be posted when available."

Witness video showed carnival goers and those leaving the concert running for the parking lots. Some claimed they hid in bathrooms and bushes until they were told it was safe to leave.

Among the conflicting reports from witnesses was how many alleged gunshots were heard and where the sound came from. Some said they heard one gunshot while others claimed they heard four or five.

Watch: Viewer video of reports of possible shots fired

Over the public address system, those still inside the stadium were asked to stay in place. Then at 10:04 p.m. the rodeo tweeted, "If you are in the stadium, please exit on the west side."

At 10:30 p.m. the all-clear was confirmed, with rodeo officials stating, "NRG Park grounds are clear to move about as normal."

KHOU 11 News producer Clay Dippel captured on a live Facebook video attendees exiting the stadium following instructions by the announcer to leave in an orderly manner.

Watch: Rodeo attendees exit stadium following possible shooting

KHOU 11 viewers shared their stories of the incident on social media: