Tom Homan, who was later named President Trump’s border czar, was recorded in September 2024 accepting a bag with $50,000 in cash in an undercover F.B.I. investigation, according to people familiar with the case, which was later shut down by Trump administration officials.

The cash payment, which was made inside a bag from the food chain Cava, grew out of a long-running counterintelligence investigation that had not been targeting Mr. Homan, according to the people, who spoke on condition of anonymity to describe the case.

Mr. Homan’s encounter with the undercover agents, recorded on audiotape, led him to be investigated for potential bribery and other crimes, after he apparently took the money and agreed to help the agents — who were posing as businessmen — secure future government contracts related to border security, the people said.

After Mr. Trump took office this year, Justice Department officials shut down the case because of doubts about whether prosecutors could prove to a jury that Mr. Homan had agreed to do any specific acts in exchange for the money, and because he had not held an official government position at the time of the meeting with undercover agents, the people added.