One San Mateo resident was contacted by a suspect claiming to be a grandson who had been arrested for drunken driving in New York, according to San Mateo police.
A second suspect claiming to be a public defender instructed the victim to wire money via Western Union to cover legal expenses.
The transaction was completed and investigators reported the pilfered money was picked up in Madrid, Spain.
In another case, a scammer contacted a San Mateo woman and claimed to be her grandson needing money to post bail in Montreal, Canada.
The victim complied with the suspect's request and wired money to England, where it was claimed by an unknown individual, according to police.
In a separate incident, a victim was contacted by a suspect who said the victim had won $500,000 in a lottery in the Philippines. The victim was told to wire money to cover supposed taxes before the prize money could be claimed. The victim completed eight wire transfers to the Philippines, where the funds were claimed and no winnings were ever delivered, according to police.
Officials are warning residents to be suspicious of telephone calls from anyone requesting that money be wired abroad and to hang up immediately and report the solicitation to San Mateo police at (650) 522-7700.