GREENVILLE, S.C. -- Even though the evidence was staring her in the face, Sarah Cooper of Lexington County had no idea her 88-year-old father was being scammed.

"I didn't know it. I didn't notice it. I just thought he was okay, you know," Cooper told News 4's Tim Waller in an interview at her home on Lake Murray.

Her father, a retired banker who watched every penny, sent $4,000 to scammers between January and May of this year.

"He was very frugal," said Cooper. "That's why some of the changes that I've noticed were so shocking to me, because he was spending money and normally he wouldn't have done that."

His daughter intervened. She closed his checking account and replaced his check card with an ATM-only card.

Even now, dozens of junk letters arrive every day, requesting money for questionable charities and sweepstakes.

"There are a lot of people in their 80s and 90s that wouldn't fall prey to a scam for anything. I mean, they're sharp, they're right on it, and then, whoops, guess what? They fall for it!" said Vickie Williams, Director of Aging Services for the Appalachian Council of Governments.

Williams said most scams that target seniors can be easily prevented with help from the family, especially adult children.

Williams offered these tips:

Check your parent's mail to see if there has been an increase in charity, sweepstakes and other junk solicitations.

Keep an eye on their financial statements, and check for any unusual transactions.

Arrange a meeting with someone at their bank who can alert you to any suspicious activity on their accounts.

"You know, is it OK if I go to the bank and tell the bank you deal with if they see something unusual, because mom you may not catch it, that they call me and let me know," Williams said.

Also, look for unusual lifestyle changes that may signal a sudden drop in income.

Finally, have a talk with your parents and explain how things have changed since they were young. Also explain how scams work.

Sara Cooper said her father is embarassed by what happened, but is thankful his family got involved.

"We've made a believer of him," Cooper said. "He almost welcomes the protection."

Resources:

Lieutenant Governor Andre Bauer's Task Force on Senior Fraud:

Appalachian Council of Government:

Scam descriptions from AARP:

MSNBC Protect your family from senior scams: