A Secret Service spokesman would not comment Thursday, saying the investigation is ongoing.
On the artist's website, Kyle McDonald describes the project as "People Staring at Computers 2011 A Photographic Intervention." A video shows patrons in an Apple store gazing at a computer screen in which photographs of other faces pop up.
McDonald told The Associated Press Thursday that he's in contact with the civil liberties group Electronic Frontier Foundation. He says they encouraged him not to discuss the project while it's under investigation.