Privacy experts said thieves are taking identity theft to a whole new level in the form of scam that is being touted as the most sinister yet.I had a woman who called me who had found out that someone used her Social Security number with a different name to work, said attorney Mari Frank.Seven years later, the Internal Revenue Service tracked down Franks client.(The IRS) had charged her with thousands of penalties and fees and were going to literally put her in jail, said Frank.Franks client was a victim of what is known as synthetic identity theft.Unlike traditional identity theft, thieves steal a persons Social Security number but tie it to a different name and create a new, fictional person that experts said is hard to detect.So, it is actually more insidious and more frightening for a victim, said Frank.According to experts, thieves open bank accounts and credit cards, or even obtain jobs. Yet it can take years for the scam to be uncovered because it is difficult for authorities and creditors to unravel all of the mismatched information.Five years ago, this crime was hardly seen, but Stephen Coggeshell of ID Analytics said, Eighty-five to 90 percent of identity fraud is really this synthetic ID fraud, as opposed to the true name identity theft."Since the fraud isnt committed in your name, it typically does not show up on your credit report because not enough of the ID information matches you. However, your stolen Social Security number could end up in all kinds of different databases, including those used for background checks.Privacy expert Chris Hoofnagle said, What synthetic identity thieves do is pollute the files."This act could affect consumers who are seeking a loan or job seekers applying for employment.Hoofnagle said the trouble isnt always financial.I had another gentleman, his Social Security number was used by someone who was tried for murder, and so every time there was a background check that pulled up his name, it linked these other databases showing him as arrested for murder, said Hoofnagle.To find out if youre a victim, experts said there are steps you can take.Look at your Social Security statement that you receive once a year from the government carefully and make sure that there isn't income on there that you didn't actually earn, said Hoofnagle.Without checking the statement, the IRS could end up knocking on your door, experts said.If you receive a large portion of mail in someone elses name, it could be a sign that your information is at risk.Your Social Security number right now is the key to really destroy your life because if someone uses it with or without your name, it still can come back to haunt you, said Hoofnagle.While synthetic identity fraud does not typically show up on credit reports, experts said it is still critical to check credit reports yearly to verify all activity.