No such luck. The debt collector resold the debt. On July 18, another debt collector, Merchants Credit Guide of Chicago, sent a demand letter to the Slotnicks — this time for $982. The Slotnicks sent off another copy of the death certificate, but not before Allan Slotnick had a telephone encounter with a collector who hung up on him. "He refused to listen. He just wanted the money," Allan Slotnick said.

"It's very upsetting to get this kind of a reminder of our son's death after all these years," Marjorie Slotnick said.

Abusive tactics

Regulators and specialists in consumer debt say the number of mistaken-identity cases is growing.

William Lund, chief of Maine's Office of Consumer Credit Regulation, which has taken aggressive action against some debt collectors, said the incidence of collectors chasing the wrong people has increased dramatically in the last five years. Lund blamed the problem on the growth of the debt-buying industry, hundreds of companies that buy old debt, often with outdated, insufficient or inaccurate information about debtors. Last year, for instance, debt-buyers purchased $66.4 billion from bank credit card issuers alone, up from $4.4 billion in 1995.

Knowing that debtors move frequently, debt collection firms commonly rely on databases to locate and go after people with the same name in the same general geographic area, according to Lund. Too often, as the Globe determined in several cases, such identifications are wrong.

But when consumers proclaim their innocence, the result is often an angry impasse. The collectors, citing federal privacy laws, will not share information about the debt with consumers who claim not to be the debtor. And debtors, asked to prove their innocence, are seldom willing to do so by sharing their Social Security numbers with strangers, especially unpleasant debt collectors.

"It's an unfortunate and abusive game that is played," Lund said.

Deborah Donovan is a case in point. Allied Interstate Inc., a national collection agency that works for creditors, was trying to collect on a Sears credit card debt that is owned by a subsidiary of Sherman Financial Group, a major player in the debt-buying industry. The account wrongly identified Donovan as the debtor. Allied's own database-verification effort did not catch the error, according to Gregory E. Harmer, the general counsel for Allied.

As a result, Donovan, who is disabled, suffered a summerlong headache. In April, she received a demand letter. The calls started in May. "I told them I never had a Sears card," Donovan said. The Allied debt collector then demanded to know her Social Security number. Donovan refused. "The woman was very abusive. She said, 'We're going to keep on calling you and keep on sending you bills until you tell us,"' Donovan said.