Vancouver police believe a suspect know as the "Ring Cleaner" may be responsible for stealing three priceless rings from a 91-year-old woman recovering from surgery.

"We do have a prime suspect," Const. Tim Fanning told CTV British Columbia Wednesday. "But there's other people that may be involved and that's what the detective are doing right now -- sorting it all out and piecing the file together."

He said the suspect has a history of targeting seniors in hospitals.

On Saturday, the thief walked into Agnes Ulmer's room at the Vancouver General Hospital and offered to take her jewelry for a cleaning.

Ulmer, still medicated after having her leg amputated because of a blood clot, agreed.

The thief, who was caught on surveillance cameras, never came back.

On Tuesday, speaking through tears, Ulmer said one of the stolen rings was her "mother's, mother's ring."

The man also stole the wedding band Ulmer has worn for nearly seven decades.

"(He said) I'll have them done in about 10 minutes," she recounted to CTV British Columbia.

The surveillance footage shows a white male, dressed in dark clothes and a baseball cap, leaving the ward carrying a bag.

Ulmer's family is outraged at the VGH and the company contracted for security at the hospital.

Paladin Security's Leo Knight told CTV British Columbia that his company is doing all it can to keep patients safe.

"We'll be responsive to whatever the Health Authority wants us to do," said Knight. "You can secure any building and make it as tight as you want. The question is how much is it going to cost and how much are you going to spend in emotional issues with families and patients?"

Knight said the suspect in this case is believed to have struck six different times at four different facilities since 2005.

For Ulmer, catching the thief comes second to getting her jewelry back.

"Just bring back my ring. You can have my leg, you've got it, but I want my rings, please."

With a report from CTV British Columbia's Stephen Smart