The group sent a statement to the newspaper explaining the vandalism was a response to President Trump's administration's "blatant disregard for the environment".
WaPo's opening line in its report was, "A group of environmental activists pulled off a daring act of defiance at one of President Trump's premier golf courses early Sunday morning".
The Los Angeles Police Department are investigating whether the act constitutes vandalism or accidental, while a group spokesperson told the Washington Post they used "gardening tools" and that it took less than an hour. "NO MORE WOODS", the statement said.
Sgt. Thomas Anderson of the Sheriff's Lomita station said authorities received a call about 8:30 a.m. about possible vandalism at the golf course. Photos and video show a group clad in dark clothing making their way onto the green of the golf course with rakes under the cover of night.
"Repurposing what was once a lovely stretch of land into a playground for the privileged is an environmental crime in its own right", one of the vandals said.
"We hope this sends a message to Trump and his corrupt administration that their actions will be met with action", the member added. The Trump National Golf Club is an 18-hole public course that charges an annual membership fee of $695 on top of a $160 fee to play each visit.
The golf club was opened in 2000 on what was previously farmland.
This isn't the first time a Trump property has been vandalized in recent months. Last October, a group of activists spray-painted the phrase "Black Lives Matter" at the brand-new Trump Hotel in Washington, D.C., during a demonstration, according to Politico.
The artist collective, known as INDECLINE, displayed a naked statue of the then-candidate in several cities, including Los Angeles, in August 2016.