WASHINGTON — The cryptically worded request marked urgent from the State Department’s independent watchdog set Congress on edge.

The message, according to Steven A. Linick, the department’s inspector general, was that he needed to meet — and right away — with senior congressional staff members to give them copies of documents related to the State Department and Ukraine. He signaled that they could be relevant to the House investigation into whether President Trump pressured Ukraine to investigate former Vice President Joseph R. Biden Jr. and his son Hunter Biden.

Some Democrats prepared for an explosive revelation that might show top administration officials had tried to obstruct their work. Speaker Nancy Pelosi told lawmakers on a caucus conference call that news reports were confirming that the heart of the briefing was about the White House retaliating against State Department staff who complied with the investigation. Representative Elijah E. Cummings of Maryland, the chairman of the House Committee on Oversight and Government Reform, called Mr. Linick’s request “significant” and told lawmakers to “stay tuned.”

So what congressional aides received — a roughly 40-page packet of documents sheathed in a manila envelope decorated with cursive script and manipulated to look aged, with a return address portraying that it had come from the White House — may have been a bit of a letdown.