If you've ever feared your elderly mother or father might be scammed over the phone, then consider the story of Arthur Halprin, 82, retired physics professor living in Newark, Del.

A "sharp cookie" and a brilliant teacher, say friends and family, Halprin was swayed by a flimflam aimed at the elderly, known as the "impostor scam."

One morning last month, he got a horrific call from a strange number. It was a man who claimed he'd kidnapped Halprin's adult son, who resides on the Main Line. The man said he was holding Halprin's son at gunpoint and was demanding $5,000 in ransom.

"Dad, please help me!" was the first thing Halprin heard.

"I've never been taken [in] by any computer or other scams like the Microsoft or the IRS. I knew those were phony," Halprin said. "This one I'd never heard about. It's one that you can't take a chance on. A voice called my cellphone, and the person sounded enough like my son to me, it was believable. That's the way it started."

"Then someone else got on the phone, asked me, 'Is there anyone else around you?' I said 'no.'"

In truth, his companion, Shelley Sarsfield, was listening from the other room. But Halprin didn't want to lose contact.

For the next hour, the caller kept Halprin on the line. "I wrote down on a piece of paper that 'criminals have Dan,' and gave it to her. I left the house in my slippers still and got in the car" to drive to the bank.

From her telling, Shelley Sarsfield, 68, was instantly suspicious.

"I was there when the phone call came in. We'd had breakfast and I heard Arthur talking loudly. He's normally very soft-spoken, but he'd been concerned about the stock market, so I thought perhaps he was talking to his broker about Tesla's stock price."

Halprin handed her a crumpled piece of paper.

"I knew it was a scam," she recalled. "I'd heard about the 'grandparent scam,' when con artists pretend to be someone's grandchild and call up asking for bail money. But his son is 47 years old! I knew it was wrong, but I couldn't get Arthur to listen. It was his son's life at stake. And they wouldn't let him put down the phone — that's part of the con."

Halprin's son works for a nonprofit in Philadelphia, so Sarsfield called his son immediately. Luckily, he answered and told her he was at work and perfectly fine.

"I insisted he call me back on Facetime to prove he wasn't under duress. Then I called the police," she said.

Halprin, meanwhile, drove to the bank and withdrew $5,000 in cash — without any questions from his bank teller. Then the caller directed him to the closest Walmart to wire the money to Puerto Rico.

Sarsfield couldn't get Halprin on the line, but she asked the Philadelphia police to connect with their local counterparts, aided by Halprin's license plate number and a physical description. She also heard the scammers demand he wire money from the nearest Walmart.

Halprin, indeed, made it to the Walmart nearest his house, and while standing in line, "I did finally see a text message from Shelley, saying 'Dan is OK.' I wasn't sure how she knew this. But even while on the phone with the scammers, it made me pause just long enough at Walmart for a policeman to come up to me in line. He asked if I was Arthur Halprin, and said 'Your son is OK, this is a scam.' I breathed a sigh of relief. I still had the scam artist on the phone. The cop got on and said 'this is sergeant so-and-so. Go ahead and shoot Dan if you want.' They hung up."

Halprin was minutes away from wiring $5,000 to a stranger. So why did he fall for the flimflam after hanging up on so many others?

"This was one where potentially someone's life was on the line. It wasn't the threat of jail or taxes. It was my son's life. There was just – I couldn't risk it. Whatever suspicion I had, I had to bury, I couldn't be sure. They knew my son's name. They figured out who my kids are. It was a very close call."

Financial advisers such as Dan Roccato at Quaker Wealth Management in Moorestown say the root of the crimes "is love or loneliness. Imagine you're an 80-year-old widow or widower, and you don't have a lot of human interaction. You get a phone call from your grandson you haven't seen or talked to in a long time and you love them, so you send the money."

About 550,000 people who gave their age  reported fraud to the FTC in 2017, a fraction of the true victims. Of those, more than 107,000 were age 60 to 69; more than 62,000 were 70-79, and more than 28,000 were older than 80. Among the top frauds? Impostor scams.

To prevent such crimes, Roccato advises friends and family members to make sure the elderly person in your life "isn't on his own or her own all day every day. Even just a phone call, a text, a visit is important so that person feels a connection is still there."