PITTSBURGH -- The person that was supposed to be protecting the painting “Night Sky 12” was accused of defacing it beyond repair on Thursday.

Visitors said they were shocked to find out that this defacing was an inside job. Timur Serebrykov, 27, who was employed as a security guard at the museum, was charged with felony institutional vandalism. Surveillance video was recovered by police shows Serebrykov cutting a large vertical gouge into the painting. Court documents state that when questioned by museum officials, he denied doing wrong. When police were brought in, he changed his story telling them, “I did it with a key. I didn’t like the painting. I’m sorry.”

George Matta, a museum visitor, said, “Thank God that everybody who doesn’t like something doesn’t take a destructive manner in doing it. Maybe he should look for another job.”

“Night Sky 12” is valued at $1.2 million and was the work of artist Vija Celmins, born in Latvia. She fled with her family to Germany before the Soviet Army in 1944 and then emigrated to the United States.

A museum representative would not comment on the incident, but said that the painting can be repaired. However the museum’s chief conservator told police this valuable painting was a total loss.