Treasury Sect'y Steve Mnuchin and wife Louise must have been naughty this year -- as some say -- because he didn't even get coal for XMAS .. he got a package of s***.
The Mnuchin's have a home in Bel Air and law enforcement scrambled to his address Saturday night after a suspicious package addressed to the Treasury Secretary was found in a neighbor's driveway.
The package label said the givers were "The American People."
Turns out the package contained horse manure.
The couple has pissed off many Americans for their in-you-face lifestyle ... especially Louise's, who flaunts her designer clothes with a Marie Antoinette attitude.
The Secret Service is investigating.