Philadelphia defense attorney Michael T. van der Veen recently broke down the evidentiary standards for these rare trials in Newsweek. He noted that the absence of a victim's body does not create a legal impasse for prosecutors. Instead, the state relies on building a "corpus delicti"—the body of the crime—through a mosaic of circumstantial evidence, digital records, and witness testimony.

Van der Veen explained that legal precedent allows juries to weigh circumstantial evidence as equal to, or occasionally stronger than, direct physical proof. By tracking disruptions in a victim's established routines, investigators can often lay the foundation for a criminal charge. In Guthrie’s specific circumstances, the necessity of her medical care provides a critical anchor for the prosecution’s narrative, making the theory of an accidental or voluntary disappearance statistically improbable.