This gold box by Bill Reid with a sculptured eagle on top was one of 15 art objects stolen from the UBC museum overnight Friday. (UBC Museum of Anthropology)

Interpol has joined the hunt for several art "treasures," including 12 pieces by renowned Haida artist Bill Reid, stolen from a museum in B.C.

In another development, a $50,000 reward is being offered for their safe return.

The RCMP had little to say on Monday about their investigation into the theft at the Museum of Anthropology at the University of British Columbia in Vancouver, but said they have sent descriptions of the art works to Interpol, the world’s largest international police organization with 186 member countries.

Const. Annie Linteau said it was a case of forced entry but wouldn't say exactly how the museum's sophisticated security system was breached.

Security guards discovered the heist Saturday morning and immediately called police and museum staff. Twelve works by Reid along with three Mexican pieces vanished overnight Friday, the museum said.

The gold in the art works is worth more than $15,000, but the pieces have been appraised at about $2 million, said Scott Macrae, UBC's executive director of public affairs.

Three bracelets consisting of gold-coloured Mexican coins from Oaxaca Mexico like this one were stolen along with 12 pieces of Bill Reid jewelry. (UBC Museum of Anthropology)

The university and the museum are offering the reward for the safe recovery of the works in their original condition and the arrest of suspects involved in the theft by June 30, Macrae said.

"The theft of these art objects is a loss of cultural patrimony for the whole of Canada," Anthony Shelton, the museum's director, said Monday.

"We are working with the RCMP as they conduct their investigation, and are hopeful that these cultural treasures will be recovered safely."

There has been speculation the pieces may have been stolen to be melted down for their gold, while another theory is that thieves may have entered with a list drawn up by a collector.

In either case, it's clear the break-in wasn't random, museum curator Bill McLennan said.

"There's no question about it that they [the stolen pieces] were targeted," McLennan said Monday as he sat in front of a conspicuously empty case in the museum's Bill Reid exhibit.

"They brought in with them the equipment to do the job on some very high security cases. I think they must have had a fairly decent sense of what they were doing and what they were going for," McLennan said.

With files from the Canadian Press