Va. Code Ann. § 19.2-202

At least four of a regular grand jury must concur in finding or making an indictment or presentment. It may make a presentment or find an indictment upon the information of two or more of its own body, or on the testimony of witnesses called on by the grand jury, or sent to it by the court. If only one of their number can testify as to an offense, he shall be sworn as any other witness. When a presentment or indictment is so made or found, the names of the grand jurors giving the information, or of the witnesses, shall be written at the foot of the presentment or indictment.