(CNN)The Hmong Cultural Center in Minneapolis is having to push back the opening of its expanded museum after vandals defaced the front of the building.
Mark Pfeifer, the director of programs for the center, told CNN he discovered the vandalism Wednesday.
"I saw it right away and my heart sank. It was so depressing," he said.
White paint covered the front of the museum and the new sign advertising the museum, which had just come in after almost a month of waiting.
There were also a few words stenciled into the paint, Pfeifer said, that read "life, liberty, and victory."
Pfeifer said they had to order another sign and they are working with the building owners on a cleanup plan, as well as adding extra security.
"We've gotten racist emails and calls in the past, but nothing like a vandalism act like this," he said.
They did have some broken windows from a protest last year, Pfeifer said, but the damage was not specific to their building -- several others on the block had damage as well.
Police are investigating and looking at security footage, but Pfeifer said the vandals were wearing masks and caps, so it's hard to make out their features. He said staff are hoping someone witnessed the crime and can provide some leads.
"It feels awful. I worked so hard, along with the staff, on this museum for the last couple years," he said. "All (the community) knows about us is this incident ... and I'm just hoping in the end something positive will happen."
The Hmong Cultural Center's museum is the only free-standing Hmong museum in the country, according to Pfeifer. The mission of the center is to promote cross-cultural understanding in Minnesota and nationwide.
The center teaches about the culture, history and the cultural contributions of Minnesota's Hmong community. They include Sunisa Lee, the US gymnast who won three Olympic medals in Tokyo.