If you receive a target letter, you want to avoid ignoring it altogether. After all, if you have received a letter, the U.S Attorney has accumulated and presented enough evidence in order to legally obtain an indictment from a grand jury. Therefore, by ignoring the letter, you will pretty much guarantee an indictment. Keep in mind, the grand jury is usually presented with the evidence from the U.S Attorney and federal agents along with any cooperating witnesses in privacy.
Thus, if you don’t respond to the letter, the U.S Attorney along with the grand jury will not be able to get your side of the story including any evidence you have or your perspective as it relates to the charges against you.
Never contact any individual that you might believe may be involved with the case. By doing so, you will likely be obstructing justice which can result in further punishment and charges being filed against you. Never destroy, manufacture, or change evidence. Doing so will likely lead to further charges being filed against you and it can result in even harsher punishment upon sentencing. Lastly, never engage in any type of interview nor discuss details with agents or prosecutors involved with the case.
If you believe that you are not guilty, any statement that you make can and will likely be used against you. Therefore, you need to be careful about presenting your side of the story to the U.S Attorney to effectively give yourself the best chance of beating the case.
To put it simply, no. One only receives a letter if the U.S Attorney does not have any reason to believe the suspect will tamper with witnesses, destroy evidence, or otherwise. In these cases, they will not be notified and they will be arrested immediately after they are indicted by a grand jury. Any individual who was arrested while they were in possession of drugs is not likely to be notified ahead of time prior to getting an indictment from a grand jury.