WATERVILLE — City police are warning that scam artists using computers to alter the caller ID that appears on victims’ phones are preying on elderly people by pretending to represent an entity they call the National Gaming Commission.

Deputy police Chief Charles Rumsey said in a press release an 84-year-old woman got a call this week from a man who told her she had won a multi-million dollar sweepstakes, then convinced her to buy two pre-paid debit cards for $700 to claim the prize. A family friend became concerned and called the police.

While a police detective was interviewing the woman, the man called again and tried to get the woman to give him the account information that would have allowed him to steal the money on the card, according to the release.

The detective intervened, but the man continued to call, Rumsey said.

The caller is using a technique called spoofing, in which a computer is used to created a fake caller ID that appears on the victim’s phone, often looking legitimate.

Police say residents should be aware that no legitimate contest would require a person to spend money to claim a prize.

Detective David Caron is investigating the scam, according to Rumsey, who said police learned that calls to the victim’s house appear to be originating from outside the United States.

Two different men who called the victim had strong Middle Eastern accents, although residents should be wary whether a caller has an accent or not, Rumsey said.

People who may be victims of such a scam should call the local police department, he said.