Va. Code § 52-8.1
In addition to any other powers and duties which may be provided by statute or otherwise, the Bureau of Criminal Investigation shall conduct an investigation into any matter referred to it by the Governor. The Bureau of Criminal Investigation shall, when requested by the Attorney General, any sheriff, chief of police, attorney for the Commonwealth or grand jury, conduct an investigation into the subject matter so directed or requested, if the person or grand jury making the request has reasonable cause to believe the acts committed or about to be committed would constitute a Class 1, 2 or 3 felony, to determine whether any such criminal violations have occurred, are occurring or are about to occur. The Bureau may, in all other requests for investigations made by the Attorney General, any sheriff, chief of police, attorney for the Commonwealth or grand jury, conduct an investigation into the subject matter so requested, to determine whether any criminal violations have occurred, are occurring or are about to occur.
Va. Code § 52-8.1