Police in Belleville are investigating after a masked man showed up in the background of a KMOV (Channel 4) live shot Wednesday, resulting in the station cancelling a live report during its 5 p.m. newscast.

Reporter Brittany Noble was scheduled to do a live "stand-up" introduction to her report about a string of thefts from construction sites in southeast Belleville.

Shortly before air time, Noble and cameraman Alonzo Medcalf noticed a man wearing a white mask pacing in the background and occasionally ducking behind a truck, KMOV news director Brian Thouvenot said.

"The man went away, then came back (with a different mask)," Thouvenot said. "So for the safety of our crew, we decided to cancel the (live) shot."

The crew went to the van and called Belleville police, Thouvenot said, adding that Medcalf kept the camera rolling and collected footage of the masked man.

Later, Noble posted some video of the man on her Instagram account. She also wrote: "I wanted to go live @5 today but this guy kept watching me so I called police. If you know who he is contact them."