An 82-year-old woman told a Toronto courtroom on Tuesday that a telephone caller, posing as a social worker, lied her way into her home, then stole her credit card two weeks after her husband died.

Frances Mason testified Tuesday in the trial of Carol Williams, 47, who faces 54 charges, including fraud and theft totaling $100,000. Police believe Williams committed the crimes with a former Sunnybrook hospital employee named Lorraine Pinnock. Police allege the pair posed as social workers to get access to seniors' homes and steal their credit cards.

Pinnock pleaded guilty last year to similar fraud charges and appeared in court Monday as a witness for the Crown.

Williams has pleaded not guilty to the charges.

Outside the courtroom on Tuesday, Mason told CBC News she received a phone call from Williams in November 2009, two weeks after the death of her husband Charles, a veteran of the Second World War.

He spent the last five years of his life in long-term care at Sunnybrook.

"I received a call from a lady stating she was from Sunnybrook Hospital," Mason said. "Because she had known my husband has been in Sunnybrook for so long. And could she just come and just see that I was being cared for in the way that they thought I should be looked after."

Carol Williams, shown in this courtroom sketch, has pleaded not guilty to 54 charges including fraud and theft totaling more than $100,000. (Alex Tavshunsky/CBC)

Mason said once Williams was inside her house, she distracted her by requesting a cup of tea.

"She wanted to see that my health card was okay and my credit card was okay," said Williams. "Then she asked for a cup of tea. I went into the kitchen and made it for her. Just two days later when I went to look for [my credit card], I couldn't find it."

Mason called her daughter-in-law, who advised her to notify the credit card company and the police.

Police allege Williams stole Mason's credit card then maxed it out with $2,000 in purchases at a jewelry store and at Staples and Wal-Mart.

'I was horrified'

The card had a $10,000 limit, but Mason said she had used it for her husband's funeral expenses, leaving less than $2,500 before the card reached its maximum.

"I was horrified," Mason told CBC. "There's a trauma to it. You just can't believe that anyone could do such an unkind thing. It's just unbelievably devastating."

Elaine Mason, Frances's daughter-in-law, told CBC she was stricken by the timing of the alleged fraud.

"Two weeks after her husband had died, just a week since the funeral. It's just so cruel," she said.

Police say the alleged targets were all elderly women between the ages of 81 to 96 years old.

Pinnock, 44, told the court on Monday she committed a handful of frauds with Williams, with the pair splitting the profits.

Mason is the first of 12 alleged victims scheduled to testify at the trial, which continues Wednesday and is expected to last three weeks.

With files from CBC's Ivy Cuervo