DENVER — The giant blue horse sculpture outside of the Denver International Airport, was vandalized, the airport confirmed.

Alex Renteria with DIA said orange graffiti was found on the horse's legs around 8 p.m. on Thursday.

“We cannot make out what is says or anything at all," she said. "It is pretty faint so it is hard to make out.”

The horse sculpture is called "Mustang," though it has earned the well-known nickname "Blucifer."

She said crews are trying to decide how to remove the graffiti without damaging the sculpture. They were working at the sculpture Thursday evening and will be out there Friday as well.

READ MORE: 'Blucifer': Is he cursed? Is he art? Coloradans weigh in on Denver's eerie-looking mustang

“This is pretty disappointing," Renteria said. "This is a piece of art that Denver residents and non-Denver residents know."

The Denver Police Department is investigating the vandalism.

This is a developing story. Stay with Denver7 for updates.