Police in Canada are on the lookout for an elderly woman believed to have pocketed a rock worth US $17,500. An ordinary river stone with the words "love yourself" written on it in black ink, the rock is part of an "interactive" art exhibition by Yoko Ono at Toronto's Gardiner Museum.

“It’s a totally interactive [exhibit], there’s a bunch of rocks on the ground and people can walk up to them and pick them up,” police media officer Gary Long told the Toronto Star. “She just picked it up and walked away with it.”

Local police put out a call for information on social media – initially undervaluing the rock at $5,000 – showing the alleged thief, a woman around 55-60 years old, in a black hat and red scarf.