ngs thr ekfowee c ahead. >>> they sound promising, bay area nanny jobs offering steady work and big paychecks. but as one local teen found out, even jobs posted on well-known reputable sites can be costly traps. tonight we go in-depth to expose a scam, preying on care takers. >> your first week on the job -- >> reporter: arianna thought she had found the perfect nanny job. >> i'm glad to receive your letter and very happy to let you know that the position is still very much open. >> reporter: she found the position on care.com, an online company that helps match families with nannies. >> i actually applied to them because they were saying how they have this wonderful job for 40 hours in gilroy, california. oh, that's so cool. it's close by. >> reporter: the pay, $700 a week was more than the 18-year-old had ever made. >> the most i would get would be like $180 a week. >> reporter: but then she started receiving e-mails from the family that she says made her feel uncomfortable. >> they sent me this picture of a big family. there were two boys. and they were really good at trying to convince me. >> reporter: arianna