They are not delaying the application. if they have to run background checks and the file goes from one person to the next, it takes time and this is not the only case they have, so it takes as long as it takes and all you can do is be patient and wait.
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Sounds like they are conducting background check. The minimum time for background check is 6 months. It may be longer in your home country depends on how quickly information can be provided by government agencies.
There is no way of ascertaining the amount of time it will take. Only the State Department knows what reviews it is conducting.
J Charles Ferrari Eng & Nishimura 213.622.2255 The statement above is general in nature, as not all the facts are known. You should retain an attorney to review all the facts specific to your case in order to receive advise specific to your case. The statement above does not create an attorney/client relationship.