'Virtual kidnapping' scam terrifying parents

Parents in Seattle, Washington, are being warned about a scam where they're told their child has been kidnapped, and the scammers demand money in exchange for their return.

The King County Sheriff's Office said the first reported occurrence of the scam was March 8 in Ravensdale, Washington. A mother dropped her two children off at the school bus, but later received a call from a man who claimed to have her daughter. He threatened to kill the child if a ransom wasn't received but the mother called the school and confirmed both her children were safe at school.

In a separate instance in Florida, a threatening phone call put a father into a panic when a caller claimed he'd kidnapped the man's daughter, but he really hadn't.

It's called "virtual kidnapping" - an extortion scheme where the scammer tries to trick a parent into paying a ransom.

Patrick McDonald got a call that literally stopped him in his tracks.

"All I can hear is a young girl crying, hysterically crying," McDonald said.

As the father of a teenage girl, the words he heard sent chills up his spine.

"'Oh, daddy, daddy, please help me,'" McDonald said he heard a young girl's voice say on the other end of the line.

Then, a male voice started barking demands.

"'Hey buddy, I have your daughter. I've kidnapped her and it's gonna cost you a lot of money,'" McDonald said the man told him.

The call was from a number he did not recognize, so he pressed the caller for answers.

"What are you talking about? I said, she's in school. He said, 'No, she's not. I picked her up.' And so he said, 'We're gonna kill your daughter if you don't pay us a lot of money by this evening,'" McDonald said.

At that point, McDonald demanded the caller put the girl back on the phone.

"And he said no, but if you want I'll cut off two of her fingers, wrap them in her underwear and ship it to you. So I just kept stringing him along because I was very very angry. He says if you hang up, I'm gonna kill her for sure," McDonald said.

He said the torturous phone call felt like it lasted a lifetime, but he knew his daughter was safe at school and now wants to warn others.

Sergeant Ryan Abbott with the King County Sheriff's Office in Washington said he believes the scammers are using social media to research the victims and gather information, such as the names of their children.

"Unfortunately, it's not just kids, parents are guilty of having too much personal information online," Abbott said.

Both of the fake phone calls came from blocked numbers.

The Kings County Sheriff's Office says to never provide money to anyone over the phone and adds the parents did the right thing in each situation by calling their child's school to confirm they were safe.

Abbott added, "Listen to what they're saying, be aware of it, take down as much information as you can, and call 911 to let us know what's going on."

The FBI said that if you get a call like this you should remain calm and never reveal your child's name or any identifying details, and report the number of the caller to authorities immediately.

ABC News contributed to this report.