A Texas woman convicted in the 2016 murder of her husband, University Park Fire Department Captain Robert Poynter, tells her story about what happened the night he died in an interview with "48 Hours" correspondent Peter Van Sant. Watch an encore of "Chacey Poynter: Witness to Murder."

With surveillance cameras seemingly on every corner, and cellphones capable of recording high quality video, many crimes are caught on camera. When fire captain Robert Poynter was gunned down in North Texas in September 2016, there was no eye in the sky to tell investigators what happened. But they did have the next best thing: police officer body cameras.

The Royce City Police Department has three of the devices and they make sure whoever is on duty has access to one. The night of Robert Poynter's murder was no different. Body cameras on two responding officers were rolling when they came across a baffling crime scene on County Road 2595 in Hunt County, Texas, about an hour northeast of Dallas.

Covered in mud and barefoot, Chacey Poynter waved down a police cruiser around 11 p.m. on that deserted road on September 9, 2016. Just minutes earlier, she had called 911.

"My husband ... he's been shot in the head! Please!" Chacey shouted.

Sergeant Shane Meek interviewed Chacey at the scene and his body camera caught all the action.

"She was just frantic. She was saying that somebody had come up and shot her husband and then she took off running," Meek said.

A police officer for 18 years, Meek had interviewed his fair share of suspects. But he'd never encountered someone like Chacey.

"This was my first murder suspect," Meek said.

When Meek initially made contact with Chacey, he believed she was a victim. As time went on, he became skeptical of her story, which she told in breathless and halting sentences.

"When I'm interviewing somebody, I analyze everything they're saying. Does it make sense? And some of the stuff that she was saying didn't make sense to me," Meek recalled. "It started seeming more and more that she was putting on a show."

As 29-year-old Chacey spoke to police, she divulged all sorts of details to them, including the fact that she was having an affair, telling Meek she'd met up with a boyfriend hours before the murder.

"Did y'all like have a date? Was it date night?" Meek asked. "No. We, we just hung out. We had sex, obviously," said Chacey.

Public Information Officer Darnell Franklin said the Royse City Police Department has been using body cameras on patrol since 2013.

"It's another tool to utilize to our advantage," Franklin said. "Some people think it can work for you or for against you, but I've seen more times when your video is rolling that it saves you than does you harm. If you are doing the right thing, there is nothing to worry about."

Hunt County prosecutor Calvin Grogan was grateful for the body camera footage.

"It was an unusual situation for him that this woman was willing to openly talk like she did at the scene," Grogan said. "He got her on camera. That's always important, to get a suspect on camera so people can see what you're seeing."

"What we call that in the business is diarrhea of the mouth. That's when you're nervous, and you don't know what to say, so you just start saying whatever your brain can jam out. And that's a good sign of someone being guilty of something," Meek said.