A Los Angeles Department bomb squad responded to a Bel-Air neighborhood Saturday night due to a suspicious package addressed to Treasury Secretary Steven Mnuchin.
Mnuchin's next-door neighbor on Bel Air Road received a suspicious package addressed to Mnuchin, according to LAPD West Los Angeles Area Watch Commander Rob Weise. The package -- which contained horse manure -- was dropped off at a neighbor's house. It was cleared by investigators around 8 p.m.
The Secret Service was also involved due to the connection to Mnuchin.
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Mnuchin was at his home at the time of the incident and "was made aware of the situation," but was not in immediate danger, Weise said.
Aerial footage from NewsChopper 4 showed officers investigating a large box wrapped in wrapping paper. Multiple law enforcement sources tell NBC investigations that officers unwrapped the box to discover it was filled with horse manure.
A Christmas card was also inside the package, making some reference to Mnuchin and President Donald Trump, multiple sources told NBC.
The card did not contain a threat, but there was some kind of negative reference to Trump's $1.5 trillion tax overhaul, signed on Dec. 22, according to multiple sources.
Mnuchin did not have to evacuate his home during the investigation, Weise said, but the investigation did force a temporary closure of Bel Air Road.
NBC News' Andrew Blankstein and NBC4's Rudy Chinchilla contributed to this report.