The probing on Tesco's accounting blunder which occurred late this year revealed "inappropriate behaviour" by staff as reported by two national newspapers on Sunday.
Tesco stated that it got its reports wrong by "overstating income and understating costs." The miscalculation was also brought about by the company not recording its payments as soon as it placed orders with suppliers, according to Reuters.
"Tesco has identified an overstatement of its expected profit for the half year, principally due to the accelerated recognition of commercial income and delayed accrual of costs," according to Tesco's official statement.
Sunday Times and The Sunday Telegraph reported that the investigation performed by accounting firm Deloitte and law firm Freshfields discovered a trend of "inappropriate behaviour" by several Tesco employees.
The Sunday Telegraph stated that a senior source directly linked to the investigation leaked the information, while Sunday Times did not cite any sources.
Tesco refused to comment on the issue about the alleged behaviour by its employees and said that primary details will be released once its own internal investigation has finished collecting information regarding the accounting scandal-together with its financial half-year report on Thursday.
The Sunday Times further reiterated that the issue originated from the first half of this year and there is no need for Tesco to recalculate reports from previous years.
On the other hand, The Sunday Telegraph reported that the profit overstatement was brought about by booking of suppliers accounts which were important to reach sales targets.
Upon realization that the goals would not be met, a "small group" of employees allegedly talked with the suppliers to still contribute to Tesco and in return, they would get "benefits" in the next financial year-benefits, which remained undisclosed but would somehow mean that Tesco would have to reimburse costs to the suppliers.
Furthermore, the insider reported that the practices have long been present in Tesco's system for over a year in a smaller scale, but immediately took off into a larger scale the last six months as sales were reportedly declining.
