(NewsNation) —  There’s a happy ending to a horrible situation, thanks to a neighbor who answered her door and saved two abused teens in the Houston, Texas, area.

Doorbell camera footage shows what appears to be two small children, barely clothed and in handcuffs, appearing to be beaten, pounding on someone’s door at around 5:30 in the morning.

In the video, one of the twins asks, “Can you please help us? We’re starving.”

Without hesitation, the neighbor says, “Come inside.”

The neighbor alerted authorities, fed the children and kept them warm until police arrived on the scene. She joined NewsNation’s Chris Cuomo on “CUOMO” to describe what happened.

“I was honestly terrified because I didn’t know what to expect on the other end of the phone. As soon as I heard their little voices, I knew something was going on and it wasn’t good,” she said.

The neighbor has chosen to stay anonymous to keep the focus on the children and their well-being. She said the twins, a boy and a girl, opened up to her about their abuse.

“They said, ‘My mom kept me in handcuffs, we just broke out of them,’” she said.

The neighbor didn’t press for answers about how long it had been happening, but she was certain some form of abuse had been ongoing due to their scars and bruises.

“There’s no way that had happened overnight. It had happened for a while,” she said.

The nurse and single mother decided to document the reported abuse, taking photos of marks on the undersized teens’ wrists and arms. She said the twins told her they had been handcuffed and zip tied at times.

Shocked at how hungry the children were, the neighbor says they told her they had not had anything to eat in a week and that they were only fed if they stayed quiet all day long.

The neighbor tried her best to help the children, but said she could not stop thinking: “Why would this mother do this? Why?”

The 16-year-olds escaped their house of horrors and knocked on multiple doors for help until they reached safety.

“They were actually going door-to-door. Some people in today’s world, you just don’t want to open your door for anyone. This woman, a single mom, took it upon herself to bring them in. Thank God she did. She saved their lives,” Harris County Police Department spokesperson Jeff McShan said.

After learning there were other children in the same home as the teens, authorities issued an Amber Alert for their other siblings, who were later located safe in Louisiana. The siblings are now in Child Protective Services custody.

The mother of the teens, Zaikiya Duncan, and her boyfriend, Jova Terrell, have been detained in Baton Rouge, Louisiana. They are awaiting extradition to Texas.

McShan called the abuse case “quite a shock” for the Texas community. He said the twins are being hospitalized for their injuries.

“It is unbelievable. They’re getting tests run. It appears that they had broken bones from previous encounters, and that they had healed. The doctors are doing a lot of tests. They were forced to drink urine and drink Clorox and they had oven cleaner sprayed into their mouths,” McShan said.

Investigators have heard the twins were severely abused and often kept inside a closet or bathroom.

“The kids were very calm, kind of an eerie calm, but they were very truthful and forthcoming about what they had been through. There’s no reason to disbelieve their story,” McShan said. “It’s horrible. Most of us didn’t sleep at all the last couple of nights just thinking, especially when we saw the pictures and had them come into the station to be interviewed.”

Duncan and Terrell are facing charges of aggravated assault with a deadly weapon. According to McShan, the deadly weapons in the case are considered to be the oven cleaner, curtain rods and an extension cord.

McShan said he’s never seen anything like this before in his career.

“It makes you wonder how much this is going on behind closed doors that we don’t know about,” he said, urging people to say something if they see something suspicious.

As for the neighbor, she wants to keep bringing awareness to the situation for the sake of the twins.

“This should have never happened. I don’t want any other kid to go through this again,” she said.

On Friday, Cuomo spoke with Cpl. Courtney Reyes and Deputy Anquanechia Tyler from the Harris County Sheriff’s Office, the officers who responded to the scene.

They detailed what they discovered after talking to the children at the hospital, including that they were forced by their parents to eat their own feces.