A box filled with manure and addressed to Steven Mnuchin, the Treasury secretary, was left Saturday at his neighbor’s home in the upscale Bel-Air neighborhood of Los Angeles, the police told KNBC-TV.

Helicopter footage from the station showed the manure spilling onto the ground after the authorities emptied the box, which was covered in Christmas wrapping paper.

A Christmas card that referred to Mr. Mnuchin and President Trump was inside the package, which was labeled as coming from “the American people,” KABC-TV reported.

The Los Angeles Police Department told the television station KTLA the package contained horse manure. The box raised suspicions and the bomb squad was called to investigate.