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.
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.