LETHBRIDGE, Alta. - Authorities in southern Alberta are warning people to be aware after an 81-year-old senior was defrauded of $250,000 in a sweepstakes scam.

Police in Lethbridge say they were contacted last week by the woman's son, who said his mother had been persuaded by scammers to send large sums of money -- mainly in the form of bank drafts -- almost weekly since last March.

She had been told she needed to send the money to cover taxes and insurance so she could claim a cash prize she had won.

Investigators have determined the senior initially received a letter purporting to be from the Bank of America and indicating that she had won a U.S. sweepstakes.

She believed the letter was authentic and over the next 10 months dealt with numerous scammers on the phone.

They continued to press her for payments and to provide her personal and banking information.