OCEANSIDE, Calif. -- Law enforcement officials are warning the public to beware of a high-stakes swindle that generally targets senior citizens and has victimized at least four North County residents since April.

The so-called "Canadian lottery scam" usually begins with a telephone call or letter announcing that the recipient has won millions of dollars through some type of drawing, Oceanside police Sgt. Leonard Mata said Wednesday.

The crook tells his targets they must post sizable payments to cover "legal fees," "international taxes" or other such bogus expenses.

"More letters and phone calls may follow to the victims, requesting even more money," Mata said.

In the latest case, an Oceanside couple lost more than $20,000, which they sent to addresses in Canada and New York over a three-month period on the belief that they were in line to receive $1.5 million, according to police.

Authorities advise the following precautions to avoid falling prey to such scams:

Never give personal or financial information to telephone solicitors
Be wary of any unsolicited communications that seek money in exchange for a cash prize or other gift
Remember that legitimate lotteries do not require winners to post bonds, legal fees or other expenses
Call the police if contacted by someone promoting such transactions
Heed the old saying: If an offer seems too good to be true, it almost certainly is