Royal Ahold NV, the Dutch owner of Giant Food Inc., told federal regulators yesterday that its accountant, Deloitte Touche Tohmatsu, no longer stands behind its audits for 2000 and 2001, raising questions about whether problems with the company's financial statements began earlier than had been acknowledged.

A source familiar with the case said, meanwhile, that the company's internal probe is focusing on two key groups of employees at Ahold's Columbia-based U.S. Foodservice Inc. subsidiary.

The company disclosed last week that accounting problems at U.S. Foodservice led to an overstatement of operating earnings in fiscal 2001 and 2002 by at least $500 million. Yesterday, in a filing with the Securities and Exchange Commission, Ahold gave the first formal indication of possible problems with reports from 2000, the year Ahold purchased U.S. Foodservice.

Ahold's internal probe is focusing on whether rebates the company received upfront from vendors were properly booked, according to a source familiar with the company. The source said investigators are looking at the role of two sets of employees -- staffers who may have been directly involved in prepayment deals that led to the restatement, as well as top executives who should have known about the problems.

The source said those men include U.S. Foodservice's chief marketing officer, Mark P. Kaiser, and Tim Lee, a purchasing executive, both of whom have already been suspended, and Chief Financial Officer Michael Resnick. Kaiser and Lee could not be reached for comment last night and have not previously returned several phone calls. Resnick did not return phone calls late yesterday.

The Wall Street Journal yesterday reported that U.S. Foodservice had ordered unusually large quantities of food and paper goods from manufacturers late last year, possibly to boost 2002 earnings. The goods reportedly were shipped to overflowing warehouses, according to the report.

A company spokeswoman said Ahold would not comment on the ongoing internal investigation, except to say the company is aware of the allegations. She said the company is cooperating fully and taking every step possible to bring the matter to a fast conclusion.

John P. Laigaie, president of Teamsters Local 628, which represents 250 U.S. Foodservice warehouse and trucking employees, said his members were not surprised by the report. He said that near the end of last year, warehouse and trucking employees of U.S. Foodservice's facility in Swedesboro, N.J., began to notice an unusually large amount of goods coming into the company's warehouse, where food is normally stored before it is trucked to local restaurants, hotels and other customers.

By late November and continuing through the end of the year, the food had filled up the warehouse so much that U.S. Foodservice directed employees to begin trucking excess frozen chickens, bottled water and pasta to three other warehouses nearby that the company rented to store the food.

"Suddenly, we're saying, 'Why are we storing all this stuff in this place? That's not our normal delivery,' " said Laigaie.

Local 628's members are former Alliant Food employees who were absorbed into U.S. Foodservice after Alliant sold its business to the company, and Laigaie said relations between the union and U.S. Foodservice have been nasty.

He said the company wouldn't explain why its truckers were suddenly being told to move frozen food to other warehouses instead of to its customers, and a U.S. Foodservice spokeswoman declined to comment.

It was "like a merry-go-round," Laigaie said. Sometimes truckers would move goods from the U.S. Foodservice facility in Sweedesboro to the rented warehouses nearby and sometimes they were ordered to truck food from the rented warehouses to U.S. Foodservice warehouses elsewhere in the state.

Although food companies may occasionally stockpile additional food at the end of the year, Laigaie said the huge volumes of food were something workers had never seen while working as Alliant employees. Workers said "this much looks like it's so much we don't see how we can ever unload it," he said.

Staff writer Sabrina Jones and news researcher Julie Tate contributed to this report.