As many rush to pay Uncle Sam before the April 18 tax deadline, scammers are trying to bait taxpayers into paying them.

"It's frightening to me," said Betty Aguilera. "I can't even imagine someone that's all alone that they wouldn't get frightened."

Aguilera said she started receiving threatening phone calls in January.

She saved one of the messages on her answering machine, and the message said it was a final notice from the U.S. Treasury. It described a legal notice concerning tax fraud her and to call a phone number before being arrested.

Worried she might actually owe something, Aguilera called.

"(He) said that I needed to get that money to him right away -- $3,700," said Aguilera.

The person on the other end then threatened to show up at her house with the police if she didn't pay up.

"It was very frightening that he knew exactly where I lived," she said.

Ron Walling got the same type of call. There was someone on the other end making threats if he didn't send money.

"(They said) 'I'm Tommy with the IRS,'" Walling said.

In the past two years, more than 5,000 people have paid out nearly $30 million to IRS scammers.

Many of the scams target the elderly, and officials say they use threats to intimidate and bully the victim into paying.

"As a taxpayer, do what you can [to] stay vigilant, keep your antenna up," said IRS spokesman Raphael Tulino.

Aguilera was lucky. She called her accountant, who stopped her from becoming a victim.

She worries about others her age that might let their guard down.

"We're good for money and we frighten easily," she said. "We don't like to owe anybody any money and I think that's why they are picking on seniors."

Experts say the IRS will never call to demand immediate payment over the phone. They will have mailed you several bills instead.

The IRS does not threaten to immediately bring in local police or other law enforcement groups to have you arrested for not paying.

Experts say the IRS will not call or email you to verify your identity by asking for personal and financial information. They also don't demand that you pay taxes without giving you the opportunity to question or appeal the amount they say you owe.