meanwhile, back at the nasa federal credit union, they got suspicious about that big cash withdrawalnd 911. police acted quickly and managed to freeze payment on 11 of the 16 gift cards. >> i think we have a good police force. and it was pure luck. the good lord was on our side. >> reporter: they seem to pick on seniors. >> yes. >> reporter: why is that? >> i guess they are more vulnerable. a lot of the seniors have stable financial means. >> reporter: if the credit union hadn't called the cops, mrs. b. said she might not have reported it. she says she was too embarrassed. police are fearful this may be other victims out there who haven't come forward in prince george's county, i'm pat collins, news4. >> man from hyattsville, maryland, has been arrested in connection with an immigration scheme. police say that he approached two women at landmark plaza last october. he told them he worked for the world bank and that he could get them citizenship. he also promised them a green card for relatives in africa. they would pay him $10,000. they did. but the suspect didn't do anything in retu

goes to the nasa federal credit union and withdraws $8,000 in cash. and then per instructions goes to walmart and buys 16 $500 green dot gift cards. >> kept saying don't tell anybody what you are doing. because it is a surprise. >> reporter: before she even left the walmart parking lot, that contest man was on the phone again. he wanted the validation numbers off of those gift cards. because once he had the numbers, the money was his. meanwhile, back at the nasa federal credit union, they got suspicious about that big cash withdrawal and 911. police acted quickly and managed to freeze payment on 11 of the 16 gift cards. >> i think we have a good police force. and it was pure luck. the good lord was on our side. >> reporter: they seem to pick on seniors. >> yes. >> reporter: why is that? >> i guess they are more vulnerable. a lot of the seniors have stable financial means. >> reporter: if the credit hadn't called the cops mrs. b. said she may not have reported it and says she was too embarrassed. and police are fearful that there may be other victims o