A Rockville woman who sent money last week in the belief that she was saving her son from being killed appears to be one of the latest targets of a telephone scam that has been spreading through the Washington area.

Montgomery County police said the woman was first asked by a caller Wednesday whether she had a son. She said she did and was then told that he had been kidnapped after a car crash and would be killed unless she wired money.

Money was transferred to destinations in Florida and Puerto Rico, the police said. Officer Britta Thomas, a county police spokeswoman, said the scam appears to target victims of all ages and ethnic backgrounds.

Accounts given Monday by Montgomery police follow a warning Friday by Prince George’s County police about the targeting of several residents there. Authorities in St. Mary’s County in Southern Maryland also have described similar efforts to defraud people.

In many of the cases, victims are told that their relative has been in a car crash and would be held hostage until money was sent for repairing the scammer’s car.

Montgomery police said that in three incidents last week, calls came from the same phone number. It appears to be local, but police said the calls actually originated from outside the United States.

Techniques exist for making a fictitious number appear on a caller identification display, Montgomery police said.

Authorities recommended that targets should refrain from giving callers information by phone and should avoid being rushed. Also, they should try to question the caller and telephone police if fraud is suspected.