Word of a possible active shooter at Memorial City Mall sparked a widespread evacuation Saturday night, though police quickly determined it was actually just a failed attempt at a smash-and-grab.

The call for shots fired came in at 7:45 p.m. after a robber with a hammer tried to shatter a jewelry case at Ben Bridge Jeweler. Afterward, he fled the store empty-handed.

Initially, police described the scene as "pretty big chaos" as they combed the upscale mall for a "possible active shooter."

The scare sent holiday shoppers and mall workers scurrying for cover, and dozens of police officers and constable deputies moved in to block off traffic.

Rafaela Dunigan was working at Bath & Body Works when the chaos broke out. First, she heard screaming and saw people running.

Then someone yelled that there was an active shooter, and seconds later people started running into the store to take cover. Dunigan, who is 19 weeks pregnant, hid in a supply closet.

"I heard glass breaking and everything falling and I knew it was because people were running through the store trying to hide," she said.

Hal Lundgren was having dinner with his wife at a nearby restaurant when he watched scene unfold off the Katy Freeway.

"It was kind of scary," he said, after spotting more than 20 patrol cars zoom by through heavy traffic on the access road as a helicopter circled overhead. "It was just flooded with police. It was kind of creepy because you know people are in jeopardy when you see that."

A picture posted to Twitter appeared to show people barricading themselves in a restroom, and witnesses said mall patrons were let out the back sides of stores.

"We were in the movie theater and lights came on that is when we knew something happened," said Jerry Gonzalez, who was halfway through watching "Murder on the Orient Express" when the lights flickered on and theater employees escorted everyone out.

"I was freaked out, coming out and seeing all the police, something like this has never happened before," said Ella Varghese, who was also in the theater.

Chantell Satterthwaithe huddled inside the Apple store after false reports of a person with a gun reached staff there. There was talk of someone with a machine gun, but it turned out to be rumors.

Jennifer Ramirez, 23, waited anxiously on her brother, Ruben, who was trapped inside the GameStop with 15 customers and employees.

"He's just locked down," Ramirez said. "No one knows what's happening."

But within an hour, authorities offered some reassurances.

"At this time, there's no evidence a shooting has occurred," police tweeted. "Very fluid, active scene."

Minutes later, Chief Art Acevedo clarified the "incident was actually a smash and grab at a jewelry store" and that "no shooting or injuries have occurred."

Although there is surveillance footage of the failed heist, police did not immediately release it. The suspect is described as 5-foot-10, 230 to 250 pounds and a white T-shirt.

"I think everything was handled pretty well," said HPD Assistant Chief James Jones told the media after.

"This was a good practice exercise for us, so I think we'll learn and determine how to do things better."

Dina Kesbeh contributed to this report.