POLK COUNTY, Fla. -

A Polk County couple married for 13 years got the scare of their lives when a man claiming to be a paramedic on the scene of an accident claimed he'd found their number in the emergency contact list of an injured woman's cellphone.

Local 6 viewers Brinda and Mike got the call on a Sunday at about 2:15 p.m.

Mike was convinced his mother-in-law had been hurt.

"She's the only other family we have in the area," Mike said.

But the tone of the call changed from medical concern to a demand for money with deadly consequences.

The caller, a man with a Hispanic accent, demanded Mike wire $3,000 via Western Union or he would kill his mother-in-law.

Polk County Sheriff Grady Judd said similar ransom calls have been tracked to Puerto Rico but they could be coming from anywhere in the world.

"The scheme depends on how vivid your imagination is and how real they want to make it," Grady said. "The whole goal is to scare the victims into rushing out and providing them with cash."

Mike said it was very frightening comparing it to a police hostage movie.

"I felt like I had my mother-in-law's life in my hands," he said.

Brinda panicked and instead of calling her mother first, she called 911.

[WEB EXTRA: Listen to the full 911 calls ]

"I was thinking my mom is gonna get killed, if they don't get any money they're going to shoot my mom," she said.

The call actually came to Mike's cellphone.

According to the report filed by the Polk County Sheriff's fraud unit, the number came from a 407-exchange that led to a burner phone.

Mike told Local 6 that the caller never mentioned him by name but he did have a location "OBT near an Exxon station."

It was all a scam. Brinda's mother was actually at home taking a nap.

Mike admits he offered information about his mother-in-law's car and her name during the call. Looking back he said that helped the con man seem even more convincing.

Judd said they have made arrests in the past but many times the con-men are never found.