AN alleged kidnapper was arrested thanks to a quick-thinking bystander at a gas station.

The stranger was using the toilet at a gas stop in southern Utah when the alleged victim slipped her a handwritten message.

The unsettling letter pleaded for “help” and contained details about her alleged kidnapper’s identity.

After she received the secret note, the unnamed witness asked if the victim was in trouble, to which she replied: “Yes.”

The innocent bystander told KSL-TV: “The lady just kind of flung the door open, she handed me the paper and said ‘please give this to police’.”

The heroic woman said she could tell the alleged victim was in “trouble” from the “second that she handed me that paper”.

She noticed the woman was visibly “shaking” and agreed to help.

The alleged victim said: “Give this to police I have to go, he’s waiting right outside, he’s right there.”

The bystander woman followed the victim back to the vehicle, and then used a clever method to capture the alleged kidnapper on video.

She pretended to use her phone, but instead recorded footage of the other woman and her kidnapper entering a Chevrolet Equinox.

The witness then followed the pair in their car and got the license plate of the vehicle.

She reported the incident to police who located the vehicle at a coordinated traffic stop around 13:30pm on March 8, eight miles south of the gas station.

Alleged kidnapper Epigmenio Bustillos Marquez, 53, was arrested and faces multiple charges of aggravated kidnapping, assault, providing false personal information to a peace officer, and damage or interruption of a communication device.

The woman witness added that the shaken victim looked terrified of her alleged captor.

She said: “I think she was really terrified that he was going to peek in and he would have seen us.

“I wasn’t panicked or anything. I was just like, ‘I’m not gonna let this lady not be helped’,” she added defiantly.

Marquez, whose movements were caught in shocking footage by the witness, bought a hot dog and drink before getting into a white Chevrolet Equinox with the alleged victim.

The alleged kidnapper also provided police with a fake ID, claiming to be a man from Durango, Mexico, according to court documents.

Investigators later found a second Mexican ID which showed his true identity.

The woman victim was also “not behaving normally” according to the officer who asked her to leave the car.

She told police she had been married to the man for 25 years, but that he had recently been showing signs of erratic behaviour.

She claimed that Marquez was supposed to be driving her to a hotel in Las Vegas where she worked, but when he picked her up he accused her of cheating on him.

She alleges that Marquez then threatened to take her to Salt Lake City or Denver and refused to let her out of the vehicle.

She further claimed that her alleged kidnapper struck her in the face and stole her phone so she couldn’t contact anyone for help.

The bystander was travelling home after a softball tournament when she happened to stop at the gas station in Cedar City, about 170 miles north of Las Vegas.