The secretary obviously has no right to retain the books and records of the club.

You could ask a lawyer to write a nasty letter. If that fails, you could sue to get them back, but it would take a very long time to resolve, your costs as the plaintiff would not be covered by insurance, and you might even have to advance legal defense fees to the secretary before you could pursue the suit. The legal system is not a very practical dispute resolution system in situations like this.

I would recommend that a small delegation of the other officers and directors go to visit the secretary.  I would advise the secretary that if the items are not returned immediately you will advise all of the other members of the club what a jerk he or she is.  And if the secretary doesn’t care about that (perhaps because the members already know), I would explain that you will have to report the “theft” to the police.  A little talk with a police officer might be more influential than anything you can say personally.

But the question raises a much broader issue for all nonprofits, and particularly for small volunteer organizations.  What would you have done if the secretary’s house had burned down and the items were destroyed and lost forever?  What type of back-up system do you have for all of your books and records?  It can be a real pain to make duplicate copies of everything, or to back-up computer systems on a regular basis.  But without a system to protect your books and records you can be seriously impaired through no one’s fault, with very little chance for recovery.