Take the letter to a criminal defense attorney. It is possible that the money was taken from you when you were arrested and not returned to you, or was used as evidence and now the evidence can be released. Confirm with a criminal defense attorney.
I am changing this from insurance law to criminal defense law.
The police want you to come pick up property (money) from when you were arrested 10 years ago? I can think of worse letters to recieve. In general, just about any State agency who may be about to dispose of property is required to give notice before doing so.
This answer is being posted as public information for the general public and is not case specific. Brandon R. Roseman is lawyer licensed to practice in North Carolina, laws very between States, you should consult your local laws and a local attorney for specific answers to your particular case. This message is not intended to create an attorney/client relationship and is not being offered as legal advice. Under no circumstances does this answer constitute the establishment of an attorney-client relationship.
I would consult with a criminal defense attorney who can find out if you have a warrant out for your arrest. As I understand, the police sometimes use tactics like these to get people to come in so they can be arrested.