The New Haven Police Department is warning residents about a possible phone scam.

About a month ago, an elderly woman received a call from someone who told her she had won $3,500. The caller told the woman she needed to pay a $500 fee to collect the money, police said.

The woman was told to buy a “green card,” put $500 on it and then a representative would meet with her.

She told the caller she was not interested and ended the call.

It’s not clear what the caller meant by a “green card.”

Wednesday, the woman received a call from the same number, and the caller, who had an accent, told her to go to the CVS drugstore in New Haven, buy the “green card” and put $350 on it.

The caller, who claimed to be in the area, spoke of coming to the woman’s home and described her neighborhood, mentioning her neighbor’s swimming pool.

The woman told the caller she did not have the money; the caller asked how much money she had; and she ended the call. She told police about the calls Wednesday. An officer dialed the caller’s number and spoke with a man, but the officer was told not to call back and was hung up on, according to police.