On Wednesday (June 1), a Dallas man broke into the Dallas Museum of Art and wound up damaging millions of dollars worth of ancient artifacts after he got into an argument with his girlfriend.

The man identified by the Dallas police is 21-year-old Brian Hernandez. Security cameras caught Hernandez holding a metal chair outside the Texas museum’s entrance around 9:40 P.M. He had broken into the museum by repeatedly striking a glass door with the chair. The footage then shows him “walking from room to room, smashing display cases and the items inside,” writes NBC News’ Claire Cardona.

Hernandez “seriously damaged” four pieces of art, Agustin Arteaga, the museum’s director, said in an interview. The Greek objects include a black-figure kylix, a bowl from the sixth century B.C. featuring vignettes of Herakles grappling with the Nemean lion; a red-figure pyxis, a cylindrical container with a lid from the fifth century B.C.; and a ceramic amphora — a tall jar with two handles — from the sixth century B.C. The other artwork that was seriously damaged was a ceramic container by a contemporary Native American artist.

Although the true cost of the destruction will not be known until officials and insurers conduct a damage assessment, Mr. Arteaga estimated that the items, which were insured, have a value of $1 million or more.

“While we are devastated by this incident, we are grateful that no one was harmed,” museum officials said in a statement. “This was an isolated incident perpetrated by one individual acting alone, whose intent was not theft of art or any objects on view at the museum.”

Hernandez was charged with criminal mischief greater than $300,000 and is currently being held at Dallas County Jail on a $100,000 bond, reports CBS News’ Julia Falcon.