Newly released video shows police rescuing a US woman bound in thick chains in the back of a van after she was allegedly kidnapped by a man and his transgender lover.

The pair planned to take the woman to a cave so they could brainwash her into marrying one of them, according to authorities.

Police pulled the van over in January after witnesses saw a woman dragged from a Las Vegas apartment less than 24 hours earlier, Associated Press reports.

Body cam video from a New Mexico police officer shows the woman sitting in the van wrapped in chains, shaking and crying.

"Oh my God, thank you," she tells police, her fists tightly clenched and hands restrained in front of her.

"Please, please lock them up," she begs officers who have surrounded the vehicle with flashlights.

Jack William Morgan, the victim's ex-boyfriend, and transgender companion Samuel Brown, who identifies as a woman, were arrested by police.

Police believe the pair had been plotting the kidnapping for more than a year.

"He dragged me out of the place, and I fought so f--ing hard cause I was like, this is how you die," the woman says.

Las Vegas police responded to the initial report and found a stun gun, knife and signs of a struggle at the victim's apartment.

A witness told police they had seen a woman being bundled into a white van with Texas number plates.

That information led to New Mexico police intercepting the vehicle and freeing the kidnapped woman.

Morgan had tried and failed to hogtie the woman, according to a police incident report.

Instead, he choked out the victim so that she lost consciousness.

Morgan and Brown pleaded not guilty to federal kidnapping charges and will face trial over the coming months.