Jury deliberations began last Thursday in the case against Robert “Gene” Pilcher. The 67-year-old was accused of the 1974 slaying of a 17-year-old girl in his cousin’s Iowa farmhouse.

It has not been easy going. Earlier this week the jury announced that they were not able to reach a verdict in the first degree murder case. On Tuesday, Judge Richard Meadows instructed the jury to continue deliberating.

Pilcher, who is accused of shooting and killing Mary Jayne Jones, maintains his innocence.

Law enforcement linked him to the killing when his DNA was discovered at the crime scene—Police recovered semen on a blanket that had been found underneath the victim’s body.

Pilcher claims that the blanket contains semen from an consensual sexual encounter and that it does not prove he had anything to do with Jones’s murder.

He also states that aside from that key piece of evidence, there is nothing linking him to the murder or any proof that he is the killer.

Another day of deliberations is done and still no verdict has been issued in the Robert Pilcher trial. Continue at 9 am

— Josh Vardaman (@CourierJosh) January 27, 2014

Pilcher was convicted of sodomy and perjury two years ago in a separate case, one with ties to the very bedroom where the teenage waitress was found dead. A woman testified that a mere three days before the victim’s body was discovered, she taken into the room by Pilcher, handcuffed and forced to perform oral sex acts.

Prosecutors in this case are banking on jurors questioning the odds: How is it that a woman comes to be sexually assaulted and held captive in the same room a the body of a woman is found in in, lying on blankets containing his semen?

Despite the prosecutions insistence, the jury continues to struggle, a fact that cannot be ignored. The semen, while linking Pilcher to the scene, may not be enough to link him to the murder. The lack of a confession and direct murder evidence may make it hard for the jury to reach a guilty verdict.

Still, the evidence, direct and circumstantial, is enough to point in the direction of possible guilt, which explains the jury’s inability to decide one way or the other.

If the jury is unable to reach a unanimous decision at all, it would result in a hung jury.

Image via KTVO TV