A US official has confirmed to CNN that the US Department of Justice has carried out a criminal investigation in Blue Bell Creameries for the company’s handling of the ice cream contamination associated with 10 reported cases of listeriosis.

Among the reported cases, three, who were believed to have got sickened by Blue Bell frozen treats, have died. Prosecutors have been examining whether the executives of the company have committed wrongdoing while handling the outbreak or not. No response has been given by Blue Bell Creameries to CNN's request for comment.

On April 20 last year, Blue Bell recalled all its ice cream, frozen yogurt, sherbet and other frozen treats sold in 23 states, after weeks of gradual recalls, and said listeria was detected on the lid of a food service cup in March.

But, the Centers for Disease Control and Prevention-led investigation has shown that the listeria outbreak dated back to 2010.

The agency has found the link between patients from 2010-2015 to the present outbreak by bringing out comparisons in database of bacteria DNA.

Last April, Dr. Robert Tauxe, deputy director of the CDC Division of Foodborne, Waterborne and Environmental Diseases, told CNN that at that time, the origin of the strain wasn’t known, however, the fact that it was the same strain in the past 5 years has suggested that it might have lurked within the factory the whole time. According to CDC, Blue Bell listeria outbreak dates to 2010.

According to a report from the CNN, Blue Bell Creameries has not responded to CNN's request for comment. After weeks of gradual recalls, Blue Bell recalled all its ice cream, frozen yogurt, sherbet and other frozen treats sold in 23 states on April, 20, 2015, after it said listeria was found on the lid of a food service cup the month before. However, an investigation by the Centers for Disease Control and Prevention showed the listeria outbreak dated back to 2010.