Manuel Oliver — father to Joaquin “Guac” Oliver, one of the 17 people killed in the mass shooting at Marjory Stoneman Douglas High School on Feb. 14, 2018 — protested atop a construction crane in Washington, D.C. Monday morning, The Washington Post reports.

“The whole world will listen to Joaquin today. He has a very important message,” Oliver tweeted, standing on the 150-foot crane.  “I asked for a meeting with [President Biden] a month ago, never got that meeting.” 

Oliver and his wife Patricia wanted to draw attention to their new intiative shockmarket.org, “a website tracking gun violence during Biden’s term as president,” writes the Post. The effort is also asking Biden to pledge substantial reform to curb gun violence during his State of the Union address, slated for March 1. The project was launched in conjunction with March for Our Lives and Guns Down America.

Oliver also hung from the crane a sign that read, “45K people died from gun violence on your watch!”, alongside a photo of Joaquin, per CNN.

“We decided to grab Mr. Biden’s attention and that crane was exactly across from the White House,” Patricia Oliver told the Post. There will be no way for Biden “to say ‘I didn’t notice it,'” she added.

The demonstration ended midmorning. Three people are in custody and facing charges of unlawful entry, though it is not entirely clear if Oliver is one of them, the Post notes.

Also on Monday, Biden released a statement to commemorate the lives lost four years ago in the Parkland shooting, saying he “stands with those working to end this epidemic of gun violence.”