Walmart and London Drugs say that fake Apple iPad 2s made of clay are also appearing on their store shelves, a day after electronic giants Future Shop and Best Buy revealed they are launching a major fraud investigation into the scam.

In most of the cases, the popular tablet computers are bought for cash and then swapped out for a piece of modelling clay. The boxes are then re-wrapped and returned to the store, only to end up back on the shelves and resold to other unsuspecting customers.

Future Shop and Best Buy say as many as 10 fake models were sold in their Metro Vancouver locations.  A Victoria resident wrote to say she purchased one of the fraudulent models at a Vancouver Island Best Buy on New Year's Day.

Since CTV broadcast its exclusive story about the frauds on Monday, more victims have come forward and two more major retailers have confirmed they're also dealing with the fake products. London Drugs said it is aware of four incidents in the past month. Walmart officials haven't provided an exact tally, but officials said they are investigating fewer than 10 cases.

Scam artists are taking advantage of the popularity of Apple's latest offering, says Future Shop spokesperson Elliott Chun.

"It's really sad that people stoop to these low levels to take advantage of really hot sellers. As you probably know, tablets were the number one touted gift items for the holidays this year," he said.

Dayna Chabot purchased a bogus 32-gigabyte iPad 2 at Walmart in Langley, south of Vancouver, on Jan. 5.

She recalls being shocked opening the "perfectly sealed" box with her boyfriend once they got home -- and seeing a block of clay instead.

"It was all sealed properly and everything. It was the shape of an iPad. They even had a piece of clay where the charger went and everything. Like, they knew what they were doing," she told CTV's Steele on Your Side in a telephone interview.

Chabot said she was immediately worried about how the retail chain would react when she brought back a hunk of clay that she paid $600 for.

"I understood that it could have easily been us that did it and went back. But they were really good about it at Walmart. They were all just kind of baffled," she said.

Chabot was given a full refund within 20 minutes after speaking with a manager. Her experience is quite different from Surrey resident Mark Sandhu, who said he was treated like a criminal by a manager when he tried to return his fake device to Future Shop on Boxing Day. He has since been given a full refund, an apology and a new iPad 2 after coming forward to CTV with his story.

For its part, Apple says it is part of the investigation, but has refused to comment on any of the frauds.

Both Walmart and London Drugs say the shrink-wrapping on the bogus products was professionally done, so the items did not look tampered with.

Future Shop and Best Buy said their policies on returning wrapped tablet computers changed in early January because of the frauds.

"We still give them the benefit of the doubt that they're coming in for a proper return or exchange … and then we will physically open it up right in front of them as well and make sure every component is there," Chun said.

Chun said in the future all iPads sold from Future Shop's stores will only come factory sealed, direct from Apple.

London Drugs is also adjusting its refund procedures for computers in a bid to prevent any more incidents. Returned computers will now be opened in front of the customer.

"It is unfortunate there are criminals who try to take advantage of our commitment to customer service and our customer-focused return policies," a company spokesperson wrote in an email to CTV News, adding that fraud is a "well-known and unfortunate phenomenon" that affects all retail business.

Walmart calls the scam "upsetting" but said it will not change its policies at this time.

All of the retailers say they are working with their loss prevention officers as well as corporate security to solve the problem.

While Walmart said it is reaching out to local police as a part of its investigation, both the Vancouver police and the RCMP say they've never heard about the scam -- and aren't involved in any probe.

A Vancouver police spokesperson said the matter would be considered civil, that is, handled within the store, until retailers seek police involvement in the process.