The death is being investigated by the attorney general's office and the state police.
His office was still investigating how many letters were sent.
The official said his office has investigated anywhere from 27 to 75 cases a year since 1988.
The medical examiner's office and the police are investigating the cause of death.
The police said the medical examiner's office was investigating the death.
No one has been charged, but the state's attorney's office is investigating.
In total, several dozen people were investigated by Walsh's office.
The Russian prosecutor's office has been investigating the case for more than a year.
He declined to identify the companies his office was investigating.
His office is also investigating charges that the supplies were sold to private schools.
