Thomas Tucker, the Richmond man who claims he left $27,000 in a Fairfax County motel last December and is trying to get it back from county authorities, appeared before a county attorney in a closed meeting yesterday to reveal the money's origin.

Tucker was scheduled to tell how he got the money, which was left in a Garfinckel's shirt box. His attorney, Victor M. Glasberg, was unsuccessful in his efforts to prevent Tucker from having to reveal the money's origin.

But Glasberg did succeed in getting a court order preventing the contents of yesterday's three-hour deposition from being made public. None of the four lawyers present in the meeting would comment on Tucker's testimony.

Tucker claims he left the money at the Brookside Motel on Rte. 1 near Groveton on Dec. 28. The money was found by a motel employee, Charles Back, who has since filed a suit claiming ownership of the money because he found it.

According to David Stitt, an assistant Fairfax County attorney, the next step in the case will be Tucker's formal request to have the transcript of yesterday' disposition sealed. A court hearing would then be held to determine if Tucker is entitled to the money.