DENVER (AP).- Investigators are trying to determine why a woman caused $10,000 worth of damage to a large expressionist painting at the Clyfford Still Museum by punching and scratching it, then removing her pants and sliding down the artwork.

Carmen Tisch, 36, faces charges of criminal mischief in the Dec. 29 attack on the painting, said district attorney spokeswoman Lynn Kimbrough.

The painting, referred to as 1957-J-No. 2, is valued at more than $30 million. The large montage of black, white and burnt orange swaths with a sliver of yellow is from Still's middle period.

Museum officials said they believe security is adequate for the facility and that they regularly evaluate security to protect the collection and visitors. Museum spokeswoman Regan Petersen said in a statement that its guards "acted swiftly and appropriately; the police were summoned immediately and the offender was taken into custody."

Denver acquired the collection in stiff competition by promising to build a facility for the paintings and sculptures. Still, who died in 1980, specified in his will that his estate had to go to an American city willing to establish a permanent museum for his work. He was one of the first abstract expressionist artists following World War II.

The museum has raised $32 million in private donations for its building, endowment and operations, Petersen said. The city of Denver also contributed about $99 million from an auction of four Still works.

Visitors touring the gallery Thursday said they were horrified by the attack. Rachel Gelbman and Christine Shaw, of Denver, said they had seen the painting at the Denver Art Museum and noticed it was missing, replaced by a similar painting from the 1956-1958 era.

To them, it wasn't the same.

"What would possess someone to do that?" Gelbman said as security guards roamed the building.

In 2010, a Montana woman was accused of taking a crowbar to a Loveland art museum display that critics denounced as obscene. Critics said it showed Jesus Christ engaged in a sex act; The artist, Stanford University professor Enrique Chagoya, said the work represented what he saw as corruption in religious institutions. Kathleen Folden was accused of damaging the print.

Tisch remained held on $20,000 bond. Court records did not indicate if she had an attorney, and no phone listing was available.

At the museum, on the wall near where Still's painting once stood, Still summed up his philosophy of art: "I never wanted color to be color, texture to be texture, images to become images. I wanted them all to fuse into a living spirit."


Copyright 2012 The Associated Press.